Stack and method of making stack

<p num="0001"> Overview The laminate includes a magnetic zero layer interposed between the crystal orientation intermediate layer and the magnetic layer. The magnetic zero layer is a magnetic layer that is non-magnetic or has a low saturation magnetic flux density (for example, B)._SThere is approximately 100 emu / cc less than the layer), and Bei particles are separated by a nonmagnetic segregant obtain. The magnetic layer contains ferromagnetic particles separated by a non-magnetic separator. The lattice mismatch between the intermediate layer and the magnetic layer over the magnetic zero layer is less than about 4%.</p>

<figref num="1">It is a conceptual diagram of an exemplary magnetic laminate.</figref><figref num="2">It is a conceptual diagram of an exemplary magnetic laminate including a plurality of magnetic recording layers and a plurality of intermediate layers.</figref><figref num="3">It is a flow diagram which illustrates the exemplary technique for producing a magnetic laminate.</figref><figref num="4a">For various exemplary laminates, the magnetic coercive force (H) with respect to the thickness of the magnetic zero layer_cIt is a figure of the graph which illustrates the change of).</figref><figref num="4b">For various exemplary laminates, the delta (H) of the magnetic coercive force and the nucleated magnetic field with respect to the thickness of the magnetic zero layer._c-H_nIt is a figure of the graph which illustrates the change of).</figref><figref num="5">FIG. 5 is a graph illustrating changes in lattice mismatch between (002) Ru in the intermediate layer and (002) Co in the magnetic layer with respect to the thickness of the magnetic zero layer for various exemplary laminates.</figref><figref num="6">For various exemplary laminates, the difference in FWHM (full width at half maximum) of the crystal locking curve between (002) Ru in the intermediate layer and (002) Co in the magnetic recording layer with respect to the thickness of the magnetic zero layer is illustrated. It is a figure of a graph.</figref><figref num="7a">For various exemplary recording laminates, the magnetic coercive force (H) with respect to the sputtering pressure used to form the Ru intermediate layer._c) Is shown in the graph.</figref><figref num="7b">For various exemplary recording laminates, the delta (H) between the magnetic coercive force and the nucleation field with respect to the sputtering pressure used to form the Ru intermediate layer._c-H_n) Is shown in the graph.</figref><figref num="8">FIG. 5 is a graph illustrating the alpha values of an exemplary laminate at various sputtering pressures used to form the Ru intermediate layer.</figref><figref num="9a">FIG. 5 is a graph illustrating magnetic core widths for various types of exemplary magnetic recording media.</figref><figref num="9b">FIG. 5 is a graph illustrating magnetic writing widths for various types of exemplary magnetic recording media.</figref><figref num="10a">FIG. 5 is a graph illustrating on-track bit error rates for various types of exemplary magnetic recording media.</figref><figref num="10b">FIG. 5 is a graph illustrating squeezed-track off-track bit error rates for various types of exemplary magnetic recording media.</figref><figref num="11">FIG. 5 is a graph illustrating on-track bit error rates standardized by track pitch for various types of exemplary magnetic recording media.</figref><figref num="12">FIG. 5 is a graph illustrating media signal to noise ratios for various types of exemplary magnetic recording media.</figref><figref num="13a">FIG. 5 is a graph illustrating the calculated areal density capacity (ADC cal) for various types of exemplary magnetic recording media.</figref><figref num="13b">FIG. 5 is a graph illustrating measured areal density capabilities for various types of exemplary magnetic recording media.</figref>

Detailed explanation Generally, the present disclosure is interposed between a crystal orientation intermediate layer and a particle magnetic layer having magnetic particles separated by a non-magnetic material such as an oxide (referred to herein as a "magnetic zero" layer). With respect to a laminate containing layers). In some cases, the magnetic zero layer is a non-magnetic layer or a saturated magnetic flux density (B) that forms part of a vertical magnetic recording medium used in a magnetic data storage device._S) Is a low magnetic layer. By including a magnetic zero layer between the crystal orientation intermediate layer and the magnetic recording layer, the recordability and / or reliability of the laminate forming the magnetic recording medium can be improved, and / or the magnetic recording medium can be manufactured. The process used to do this can be improved. For example, by including a magnetic zero layer, the magnetic coercive force (H) of the magnetic layer is compared to a substantially similar laminate that does not contain such a magnetic zero layer._c), For example, the difference between the magnetic coercive force of the magnetic layer and the nucleation magnetic field (H)_c-H_n) Or as indicated by an increase in alpha parameters, increasing the magnetic exchange-to-noise ratio of the magnetic layer, increasing the uniformity of the exchange-to-noise ratio in the magnetic layer, reducing the bit error rate (BER) of the medium, It may increase the signal-to-noise ratio (SNR) of the medium, increase the surface recording density of the medium, and / or improve other properties of the magnetic recording medium.

In some examples, the magnetic zero layer ensures that the epitaxial growth axis between the crystal intermediate layer and the magnetic recording layer is substantially maintained over the magnetic zero layer. In some cases, the use of a magnetic zero layer allows a coherent interface to be maintained between the intermediate layer and the magnetic recording layer. A coherent interface means that the lattice between the crystal intermediate layer and the magnetic layer is maintained in a substantially stoichiometric arrangement (substantially one-to-one matching mode) by elastic stress. If the interface is not coherent, the lattice changes to a non-stoichiometric arrangement (non-one-to-one matching mode) to release elastic stresses. In some of the examples discussed herein, the coherent interface is maintained when the lattice constant mismatch between the intermediate layer and the magnetic layer is less than about 4%.

The inclusion of a magnetic zero layer may allow the deposition pressure of one or more layers of the magnetic recording medium to be lower than in a deposition process that does not include the formation of a magnetic zero layer. By including the magnetic zero layer in connection with the lower pressure process, the magnetic recordability of the magnetic recording medium is maintained as compared with the magnetic medium formed by using the higher pressure process in the absence of the magnetic zero layer. It may be possible to optimize, or substantially not compromise. For example, by including a magnetic zero layer between the intermediate layer and the magnetic recording layer, the crystalline intermediate layer provides better magnetic recordability as compared to a substantially similar medium without the magnetic zero layer. However, it may be deposited by sputtering at a relatively low sputtering pressure. For example, the magnetic zero layer may provide increased exchange decoupling and / or increased exchange decoupling uniformity of the magnetic recording layer, and the intermediate layer may provide non-optimal levels and / or non-uniformity of exchange decoupling. And / or may be deposited by sputtering at a lower sputtering pressure, which would typically be accompanied by other inferior properties of the magnetic recording layer in the absence of a magnetic zero layer.

Although the present disclosure mainly describes a magnetic recording medium such as a vertical magnetic recording medium for a magnetic data storage device, the magnetic layer structure described in the present specification is not limited to such an application example. It may also be used in other application examples. For example, the magnetic layer structure described herein may be used in a magnetic sensor or a magnetoresistive random access memory (MRAM). The magnetic medium incorporating the magnetic zero layer described herein may be used, for example, in heat-assisted magnetic recording.

FIG. 1 is a schematic block diagram illustrating a magnetic recording medium 100 including a magnetic zero layer 140 interposed between a crystal orientation intermediate layer 130 and a magnetic recording layer 150. As illustrated in the example of FIG. 1, the magnetic recording medium 100 includes a substrate 110, one or more soft magnetic base layers (SUL) 120, a crystal orientation intermediate layer 130, a magnetic zero layer 140, a hard magnetic recording layer 150, and It may be sequentially configured from the protective coating layer 160.

The magnetic layer 150 of the magnetic recording medium 100 may contain magnetic particles surrounded by a non-magnetic separator material at the grain boundaries. The amount of exchange-reduced bonding of the magnetic layer is related to the separation of magnetic particles. For example, in some implementations, the magnetic particles in the magnetic layer 150 may comprise a magnetic Co or CoCr alloy, and the non-magnetic separator may comprise an oxide.

Control of magnetic exchange decoupling in the magnetic layer of a magnetic recording medium can be a factor in the dynamic recording performance of the medium, such as bit error rate (BER), signal-to-noise ratio (SNR), surface recording density. , And / or other recording performance parameters may be measured. The exchange-debonded magnetic layer may be formed, for example, by a physical and / or chemical sputtering technique that affects the growth of columnar magnetic particles separated by a non-magnetic separator that is an oxide.

For example, the formation of a magnetic layer with columnar magnetic particles can be facilitated by the shading effect that occurs during high pressure sputtering deposition. The sputtering shading effect facilitates the separation of columnar magnetic particles and the arrangement of non-magnetic separators between the particles.

First, the crystal intermediate layer below the magnetic layer may be deposited by sputtering at a high sputtering pressure (for example, 20 to 200 mTorr) to form an intermediate layer having a crystal columnar particle structure. The magnetic recording layer may be deposited on the columnar crystal intermediate layer by sputtering using a high sputtering pressure (for example, 20 to 200 mTorr) to form magnetic columnar particles of the magnetic layer. Oxide separation of magnetic particles in the magnetic layer may be achieved by reactive oxygen sputtering and / or by incorporating the oxide into the sputtering target.

According to the various examples given herein, a magnetic zero layer may be disposed between the crystal intermediate layer and the magnetic layer. The magnetic zero layer can affect the amount of exchange-reduced coupling present in the magnetic layer and / or the exchange-reduced coupling uniformity of the magnetic layer. In addition to or in addition to the techniques described above and other techniques for affecting exchange decoupling within the magnetic recording layer, a magnetic zero layer may be used.

In some cases, it is not optimal to use higher pressure sputtering techniques, for example to form columnar particle structures in the crystal intermediate layer. Because this can result in lower production yields due to redeposition area, Ar gas inclusion, blister formation, poor mechanical performance, corrosion problems, and / or other effects. Because there is.

In some cases, the incorporation of a magnetic zero layer may allow for a deposition process involving reduced deposition pressure, for example for a crystalline intermediate layer. In some cases, the magnetic medium formed by these decompression steps may provide improved recordability compared to the magnetic recordability of the medium formed at higher deposition pressures. In some cases, the magnetism of the magnetic medium formed in the decompression process remains substantially similar or substantially comparable to the magnetic recordability of the medium formed at higher deposition pressures. I have something to do.

Forming oxide-separated particles in a magnetic layer by reactive sputtering with a relatively high oxide content results from, for example, particle contamination, blister formation, steep performance gradients, and sputter arcs. Production yields may be lower. High pressure and / or high oxide content can reduce film density and crystalline core filling, both of which are negative for the recorded output signal and BER, reliability, and / or other recordability. May affect. By incorporating the magnetic zero layer, it is possible to deposit the magnetic layer with a reduced oxide content as compared with the magnetic layer of the magnetic recording medium that does not contain the magnetic zero layer.

FIG. 2 is a schematic block diagram illustrating an exemplary magnetic recording medium 200. As shown in FIG. 2, the magnetic recording medium 200 includes a substrate 228, a soft magnetic base layer (SUL) 230, a crystal orientation intermediate layer 238, a magnetic zero layer 240, a magnetic layer 242, and a protective coating 252.

The substrate 228 may contain any material suitable for use in magnetic recording media, including, for example, Al, NiP plated Al, glass, or ceramic glass. Although not shown in FIG. 2, in some embodiments, an additional underlying layer may be present just above the substrate 228. The additional underlying layer may be amorphous, providing adhesion to the substrate and low surface roughness.

A soft magnetic base layer (SUL) 230 is formed on the substrate 228 (or an additional base layer, if any). SUL230 has sufficient saturation magnetization (M)_S) And low anisotropic magnetic field (H)_k) May be any soft magnetic material. For example, SUL230 contains Fe-containing alloys such as Ni; Co; Fe; NiFe (permalloy), FeSiAl or FeSiAlN; Co-containing alloys such as CoZr, CoZrCr, or CoZrNb; or CoFe-containing alloys such as CoFeZrNb, CoFe, FeCoB, or FeCoC. It may be an amorphous soft magnetic material such as an alloy. The SUL 230 may be provided with a high magnetic permeability feedback path for the field of the magnetic read / write head from the pole.

In some examples, the SUL 230 may include a plurality of soft magnetic layers, which may or may not be separated by a non-magnetic spacer layer. In the example shown in FIG. 2, the SUL 230 includes a first SUL 232 and a second SUL 236 separated by a spacer layer 234 and made of a soft magnetic material. The first and second SUL232 and 236 may be formed from the soft magnetic material as described above. In one example, the first SUL232 and the second SUL236 may be Co-based amorphous alloys such as amorphous CoTaZr alloys or Fe-based amorphous alloys such as amorphous FeCoCrB alloys. Well, the thickness may be between about 50 angstroms and about 300 angstroms. The composition and thickness of the first SUL232 may be the same as or different from that of the second SUL236.

The non-magnetic spacer layer 234 may be formed from any suitable substantially non-magnetic material such as Cr, Ru, CoCr, Pt, or an alloy thereof. In some examples, the spacer layer 234 may function as an antiferromagnetic (AFC) bond layer that induces an antiferromagnetic bond between the first SUL232 and the second SUL236. In some examples, the spacer layer 234 may be formed from Ru to allow AFC binding, the thickness of which may be between about 4 and about 6 angstroms, or between about 14 and about 18 angstroms. However, other thicknesses are intended.

Crystal orientation intermediate layer 238 may be deposited on SUL230. In some examples, the intermediate layer 238 is used to establish a hexagonal close-packed (HCP) crystal orientation that induces HCP (0002) growth in the first magnetic layer 246 whose easy-to-magnetize axis is perpendicular to the membrane plane. You may. The intermediate layer 238 may be formed by one layer or a plurality of layers. In some examples, the intermediate layer 238 may include columnar structures comprising columnar particles and providing a basis for epitaxial growth of columnar structures in one or more magnetic layers of magnetic layer 242. As noted above, such columnar structures may be created and / or improved by sputtering deposition of intermediate layer 238 by increasing the sputtering pressure to relatively high levels. The columnar structure of the intermediate layer 238 facilitates the growth of the columnar structure in one or more layers of the magnetic layer 242 and one or more layers of the magnetic layer 242, such as an exchange-reduced bond of the first magnetic layer 246. The magnetic exchange decoupling of the

In the example shown in FIG. 2, the intermediate layer 238 includes the crystal seed layer 238a, the columnar seed layer 238b, and the columnar reduced bond layer 238c in this order. The crystal seed layer 238a may promote the thin film growth of the columnar seed layer 238b, and as a result, the crystal quality of the columnar seed layer 238b can be improved. In some examples, the crystal seed layer 238a may include NiW, NiFe, NiFeW and alloys thereof, and / or RuCr and alloys thereof. The thickness of the crystal seed layer 238a may be between about 40 angstroms and about 120 angstroms.

The columnar seed layer 238b may be provided on the crystal seed layer 238a, and the columnar seed layer 238b may have a columnar particle structure so as to promote columnar growth in the magnetic layer 242. As mentioned above, in some examples, columnar seed layers 238b may be deposited by sputtering with relatively high sputtering pressures (eg, between about 20 and about 200 mTorr) to promote columnar particle structure. .. In some examples, the columnar seed layer 238b may comprise Ru, Co, or an alloy thereof, the thickness of which may be between about 0 and about 100 angstroms.

The columnar reducing bond layer 238c may be provided on the columnar seed layer 238b. A columnar reduced coupling layer 238c may be deposited under high sputtering pressure (eg, in the range of about 20 to about 200 mTorr) to form a columnar structure, which is the formation of the columnar structure into the first magnetic layer 246. Establish a foundation for. In some examples, the columnar reduced bond layer 238c may be formed from Ru or Ru alloy, the thickness of which may be between about 40 angstroms and about 200 angstroms.

In some examples, the general structure of the intermediate layer 238 in FIG. 2 is deposited at a low sputtering pressure (eg, about 2 to 20 mTorr), a (111) Ni-W alloy or (111) NiFe (permalloy). A crystal seed layer 238a such as a crystal seed layer containing a (111) textured FCC (face-centered cubic) alloy such as a W alloy, and (002) such as (002) Ru, (002) RuCr, or (002) RuCoCr. ) Columnar seed layer 238b, which is a low sputtering pressure deposited columnar seed layer structure containing a textured HCP (hexagonal close-packed) alloy (eg, about 2 to 20 mTorr) and (002) such as (002) Ru or (002) RuCr. Includes a columnar reduced bond layer 238c, which is a high sputtering pressure deposited columnar layer structure containing a textured HCP alloy (eg, about 20 to 200 mTorr).

The magnetic recording layer 242 may be formed on the magnetic zero layer 240, which will be further described below. As shown in FIG. 2, the magnetic layer 242 may include a first (bottom) magnetic layer 246, an exchange blocking layer 248, and a second (top) magnetic layer 250. In order to control the exchange-reduced coupling in the magnetic recording layer such as the perpendicular magnetic recording layer, the first and second magnetic recording layers 246 and 250 can be formed in the exchange-reduced and bonded states, respectively. In a vertical medium, the magnetic anisotropy of the first magnetic layer 246 and the second magnetic layer 250 are each oriented in a direction substantially perpendicular to the plane of the recording layer 242 (eg, the first magnetism). The easy axes of magnetization of layer 246 and the second magnetic layer 250 may each be substantially perpendicular to the plane of recording layer 242).

The exchange blocking layer 248 may be used to adjust the vertical exchange bond between the first magnetic layer 246 and the second magnetic layer 250. In some examples, the exchange blocking layer 248 may include Ru, RuCo based alloys, RuCoCr oxide based alloys, where the oxide is, for example, SiO.₂, TIO₂, CoO, CoO₂, WO₂, And / or TaO₂including.

Each of the first magnetic layer 246 and the second magnetic layer 250 may be a particulate layer and may contain magnetic particles separated from adjacent magnetic particles by voids and / or non-magnetic materials. In some embodiments, at least one of the first magnetic layer 246 and the second magnetic layer 250 is Cr, Ni, Pt, Ta, B, Nb, O, Ti, Si, Mo, Cu, Ag, Ge. , And a Co alloy such as Co combined with at least one of Fe. In some embodiments, at least one of the first magnetic layer 246 and the second magnetic layer 250 may contain, for example, an Fe-Pt alloy or a Sm-Co alloy. In some embodiments, at least one of the first magnetic layer 246 and the second magnetic layer 250 may include alternating thin layers of Co and Pt alloys or Co and Pd alloys. In some embodiments, at least one of the first and second magnetic layers 246, 250 may be substantially free of non-ferromagnetic material between the particles. In embodiments that include particles separated by a non-magnetic material, the non-magnetic material that separates the particles in at least one of the first magnetic layer 246 and the second magnetic layer 250 is, for example, SiO.₂, TIO₂, CoO, CoO₂, WO₂, Cr₂O₃, B₂O₃, And / or TaO₂Orxides such as may be provided.

In some examples, the thickness of the first magnetic layer 246 and the second magnetic layer 250 may be between about 20 angstroms and about 200 angstroms, and the thicknesses are substantially the same as each other. Or may be different. The thickness of the exchange blocking layer 248 may be between about 1 angstrom and about 30 angstroms.

In one example, the first magnetic layer 246 has an oxide separator of SiO.₂, TIO₂, CoO, CoO₂, WO₂, And / or TaO₂CoCrPt alloy, FePt type or CoPt type L1₀Mold or L1₁It may be formed from a regular particulate alloy or a layer of Co alternating with layers of Pt and / or Pd, where the second magnetic layer 250 is one or more of B, C, Ru, and SiO.₂, TIO₂, CoO, CoO₂, WO₂, And / or TaO₂It may be formed from a CoCrPt-based alloy film containing an oxide separator such as.

For example, a protective coating 252 such as diamond-like carbon may be formed on the perpendicular recording layer 250. In another example, the protective coating 252 may include, for example, an amorphous carbon layer further containing hydrogen or nitrogen. Although not shown, in some examples one or more suitable lubricating layers may be formed on the protective coating 252.

The magnetic zero layer 240 is formed between the magnetic layer 242 and the intermediate layer 238. By interposing a magnetic zero layer 240 between the intermediate layer 238 and the magnetic layer 242, defects in the magnetic layer and / or its uniformity are increased, thereby improving the recording performance of the magnetic layer. May be good. For example, when the magnetic layer 242 is formed immediately above the intermediate layer 238, a minimum of some of the magnetic particles of the magnetic layer 242 located near the intermediate layer 238 are bonded together or separated from each other. May have non-magnetic materials. These defects lead to magnetic particles that have low or no exchange decoupling and that degrade the exchange decoupling of layer 242. In the absence of the magnetic zero layer, the magnetic layer in contact with the crystal intermediate layer tends to have reduced exchange-reduced coupling and / or reduced exchange-reduced coupling uniformity as compared to the residue of the magnetic layer.

When the magnetic zero layer 240 is interposed between the intermediate layer 238 and the first magnetic layer 246, it is the magnetic zero layer that contains many of the defects and / or non-uniformities associated with the initial deposition phase on the intermediate layer. 240. However, the magnetic zero layer 240 is non-magnetic (or B)._SIs low), so that the defects and / or non-uniformity that occur in the magnetic zero layer 240 can reduce the number and / or non-uniformity of the magnetic layer 242. The magnetic zero layer 240 may serve to increase the separation of the particles and / or to provide a more uniform separation of the particles in the first magnetic layer 246 without compromising the microstructure of the particles. In such a configuration, the magnetic zero layer 240 increases exchange decoupling within one or more magnetic layers of the magnetic layer 242 as compared to a medium having substantially the same configuration but not containing the magnetic zero layer 240. It can be made to increase the coercive force of the magnetic layer 242, increase the uniformity of exchange-reduced coupling, and / or provide other improved recording characteristics (SNR, BER, areal density, etc.). is there.

In some implementations, the magnetic zero layer applies elastic stress to the coherent interface (less than 4% lattice mismatch) between the crystal intermediate layer and the magnetic layer. Coherent interfaces with elastic stresses in the intermediate layer / magnetic zero layer / magnetic layer structure can be responsible for the improved magnetic recordability of the magnetic medium, unless one wishes to be bound by any particular theory. If the magnetic zero layer provides a coherent interface between the intermediate layer and the magnetic recording layer, the coherent stress induced by the presence of the magnetic zero may result in increased exchange loss coupling of the magnetic recording layer. In some examples, the magnetic zero layer may provide a coherent interface with increased exchange decoupling in the magnetic recording layer up to the threshold layer thickness of the magnetic zero layer. If the thickness is greater than the threshold amount, the magnetic zero layer may form a non-coherent interface between the crystal intermediate layer and the magnetic recording layer. As a result of non-coherent interfaces, the exchange decoupling of magnetic recording layers may be reduced.

For example, as described above, the first magnetic layer 246 may be a layer that is more exchange-reduced with respect to the second magnetic layer 250, and the second magnetic layer 250 is the first magnetic layer. It may be a more exchange-bonded layer than layer 246. In some examples, by including a magnetic zero layer 240 between the first magnetic layer 246 and the intermediate layer 238, the exchange-reduced coupling in the first magnetic layer 246 has, for example, substantially the same configuration. May increase beyond that exhibited by media containing but without the magnetic zero layer 240.

The increase in exchange decoupling in the first magnetic layer 246 due to the inclusion of the magnetic zero layer 240 is that the first magnetic layer 246 is compared to a substantially similar exemplary medium that does not include the magnetic zero layer 240. Magnetic coercive force (H)_c) May be affected. In some examples, the H of the first magnetic layer 246_cMay increase by at least about 10 percent or between about 2 and about 20 percent by including the magnetic zero layer 240. In some examples, the H of the first layer 246_cMay increase by at least about 3%, for example at least about 150 Oe, as compared to a medium containing substantially similar configurations but without the magnetic zero layer 240. In some examples, due in part to the increased exchange-reduced coupling provided by the magnetic zero layer 240, the first magnetic layer 246 is at least about 2% and about 100 Oe, or about 5% and about 250 Oe, or about 10%. And about 500 Oe H_cMay be exhibited. Such H of the first magnetic layer_cThe value of H is mainly achieved by, for example, the columnar structure of the first magnetic layer 240 and / or the separation of magnetic particles as described above._cIt may be larger than what can be achieved without including the magnetic zero layer 240, such as the value of.

Similarly, the increase in exchange decoupling in the first magnetic layer 246 due to the inclusion of the magnetic zero layer 240 is a first, as compared to a substantially similar exemplary medium that does not include the magnetic zero layer 240. Difference between the magnetic coercive force of the magnetic layer 246 and the nucleation magnetic field (H)_c-H_n) May be affected. In some examples, the difference between the magnetic coercive force of the first magnetic layer 246 and the nucleated magnetic field (H)._c-H_n) May be increased by at least about 3 to about 20 percent by including the magnetic zero layer 240. In some examples, the Hc-Hn of the first layer 246 is at least about 5% to about 18%, eg, at least, compared to a medium that contains substantially the same configuration but does not contain the magnetic zero layer 240. It may increase by about 150 Oe to about 500 Oe and so on. Such values for the first magnetic layer do not include the magnetic zero layer 240, for example, the values achieved primarily by the columnar structure and / or magnetic particle separation of the first magnetic layer 240 as described above. It can be larger than what is achievable.

In some examples, the increase in exchange-reduced coupling in the first magnetic layer 246 due to the inclusion of the magnetic zero layer 240 may be affected by the decrease in the alpha value. Here, alpha refers to the magnetic coercive force of the first magnetic layer 246 and the magnetic coercive force of the first magnetic layer 246 as compared to a substantially similar exemplary medium that does not include the magnetic zero layer 240. Equal to the magnetic coercive force divided by the difference between the 246 nucleated magnetic fields (ie α = H)_c/ (H_c-H_n)). In some examples, the alpha value of the first magnetic layer 246 may be reduced by at least about 1.5% to about 15% by including the magnetic zero layer 240. In some examples, the alpha value of the first layer 246 is at least about 7%, eg, at least about 0.12, compared to a medium that contains substantially the same configuration but does not contain the magnetic zero layer 240. May decrease. Such alpha values of the first magnetic layer include, for example, a magnetic zero layer 240 such as the columnar structure of the first magnetic layer 246 as described above and / or the alpha value primarily achieved by magnetic particle separation. It can be smaller than what can be achieved without it.

The magnetic zero layer 240 is preferably a non-magnetic layer, but in some cases it may be formed of magnetic and / or non-magnetic components. In some examples, the magnetic zero layer 240 may be a combination of magnetic and non-magnetic elements. Depending on the ratio of magnetic elements to non-magnetic elements, the magnetic zero layer 240 has a low B_SIt may be a magnetic layer or a non-magnetic layer. For example, the saturation magnetic flux density B of the magnetic zero layer_SMay be lower than about 100 emu / cc. In some examples, the magnetic zero layer 240 may contain at least one of Co, Cr, Ru, Pt, and oxides such as CoCr oxides. Here, the oxide is SiO₂, TIO₂, CoO, CoO₂, WO₂, And / or TaO₂Includes one or more of them. In some examples, the oxide or other isolate material is the same as the magnetic layer 242 in the magnetic zero layer 240. In some cases, the magnetic zero layer contains the same elements as the magnetic layer.

The configuration of the magnetic zero layer 240 may provide a coherent interface between the intermediate layer 238 and the magnetic layer 242, and the lattice mismatch between these layers is illustrated, for example, in FIG. 5 described below. Is less than about 4%. Elastic stresses in the lattice may be present at the interface, which affects the properties of the material. In some configurations, the magnetic zero layer has a FWHM (full width at half maximum) delta of the crystal locking curve between the intermediate layer (002) Ru and the magnetic layer (002) (eg, in FIG. 6 described below). It may facilitate heteroepitaxial growth between the intermediate layer and the magnetic layer, which is less than about 0.3 degrees (as shown). When the interface is transformed from coherent to non-coherent, the interface lattice changes to a non-stoichiometric arrangement (non-one-to-one alignment mode), releasing elastic stresses and lattice mismatch of 4%. Exceeds (Fig. 5) or delta exceeds 0.3 degrees (Fig. 6).

The thickness of the magnetic zero layer may be between about 1 angstrom and about 1,000 angstroms and may vary depending on the composition of the magnetic zero layer 240. The thickness of some examples of the magnetic zero layer 240 is less than about 30 angstroms, or less than about 25 angstroms, or even less than about 15 angstroms.

In one example, the magnetic zero layer 240 comprises a Co alloy having a Co concentration of less than about 75 atm%, for example between about 20 atm% and about 70 atm%. The Co concentration is the magnetic moment B of the alloy._SMay be less than about 100 emu / cc and substantially non-magnetic. In addition or instead, in some examples, the magnetic zero layer 240 is immediately adjacent to the HCP crystal structure, (0001) growth orientation, and the layer and / or magnetic recording layer 242 immediately adjacent to the intermediate layer 238. It comprises a material having lattice parameters substantially equal to those of the layers (columnar reduced coupling layer 238c and first magnetic layer 246 in the example of FIG. 2, respectively).

In addition or in place of this, the magnetic zero layer 240 is crystalline HCP non-magnetic or low B_SIt may contain a particulate alloy having a magnetic particle nucleus and an amorphous non-magnetic particle separator material. An exemplary non-magnetic particle separator material is an oxide (eg, SiO).₂, TIO₂, CoO, CoO₂, WO₂, And / or TaO₂), Nitride, carbide, and boride. The concentration of the amorphous material may be substantially equal to or higher than the concentration of the amorphous material in the first magnetic layer 246 adjacent to the magnetic zero layer 240. In some examples, the concentration of the isolate material in the magnetic zero layer 240, for example an amorphous material, may be greater than about 5 mol% and / or greater than about 10% by volume. .. In some examples, the crystalline particle nuclei maintain the HCP lattice parameters substantially similar to one or more of the adjacent layers of the intermediate layer 238 and the magnetic layer 242, while maintaining the magnetic saturation M of the magnetic zero layer 240._SMay contain alloying elements to reduce. Exemplary alloying elements are Cr, Pt, Ru, Mo, Mn, Ti, Cu, and other elements that alloy with Co as a relatively low concentration HCP solution (eg, about 20 to about 40 at%). May include. For example, when the magnetic zero layer contains Cr, the Cr content may be less than about 30%. In some cases, the alloying element used for the magnetic zero layer may be different from the alloying element used for the magnetic layer. In some cases, the alloying elements used for the magnetic zero layer may be the same as those used for the magnetic layer, but the proportion of elements in the magnetic zero alloy may differ from the proportion of elements in the magnetic layer. ..

The thickness of the magnetic zero layer may be inversely proportional to the content of the separator. In some cases, the effectiveness of thinner magnetic zero layers in enhancing the recording properties of magnetic recording media is made possible by incorporating relatively higher oxide content compared to thicker magnetic zero layers. You may. As previously discussed, the amount of oxide (or other isolate) in the magnetic zero layer (eg, in% by volume and / or mol%) may be greater than or equal to the oxide content of the magnetic layer.

FIG. 3 is a flow chart illustrating an exemplary technique for forming a magnetic recording medium having a magnetic zero layer between an intermediate layer and a magnetic recording layer. In some cases, the magnetic zero layer is in direct contact with both the intermediate layer and the magnetic layer. For ease of illustration, the exemplary technique of FIG. 3 will be described for the exemplary recording medium 200 shown in FIG. However, the examples are not limited to those configurations.

As shown in FIG. 3, the intermediate layer 238 may be deposited on the SUL 230 354. The deposition of the intermediate layer 238 on the SUL230 may include the sequential deposition of the crystal seed layer 238a, the columnar seed layer 238b, and the columnar reduced coupling layer 238c. The magnetic zero layer 240 may then be deposited on the intermediate layer 238, eg, just above the intermediate layer 238 356. After that, the magnetic layer 242 may be deposited on the magnetic zero layer 240, for example, immediately above the magnetic zero layer 358. The deposition of the magnetic layer 242 may include sequential deposition of the first magnetic layer 246, the exchange blocking layer 248, and the second magnetic layer 250.

Any suitable technique may be utilized to deposit the intermediate layer 238, the magnetic zero layer 240, and the magnetic layer 242. In some examples, a vacuum DC magnetron sputtering process may be used to form the respective layers in the intermediate layer 238, the magnetic zero layer 240, and the magnetic recording layer 242. Depending on the nature of the layers, a single deposition step or multiple deposition steps may be used to form separate layers. Regardless of the multiple deposition steps used to form the layer, in some cases the layer may be referred to as a single layer.

The deposition technique used may be controlled based on the composition, thickness, and other predetermined layer properties of the predetermined layer. For example, for particulate layers, sputtering may be performed in an oxygen environment to produce oxides that separate the material in the deposited layer. In such an example, the oxygen concentration may be changed to control the concentration of the separating material. Alternatively, a target containing an oxide material or other non-magnetic separation material may be used to sputter deposit layers with an optimized particulate composition. As noted above, the intermediate layer 238, the magnetic zero layer 240, and / or the magnetic layer 242 may be deposited by sputtering to form a particulate layer. The magnetic zero layer 240 and the magnetic layer 242 may be a particulate layer containing particles separated by an oxide or other non-magnetic separator.

As another example, as noted above, the sputtering pressure used during sputtering can affect the columnar structure of the resulting layer. In some examples, the sputtering pressure used to deposit one or more layers 238a-c of the intermediate layer 238 and / or one or more layers 246, 250 of the magnetic layer 242 is applied so that the layers have a columnar structure. You may select to. As noted above, in some examples the sputtering pressure may be chosen to provide columnar structures for the intermediate layer 238 and the first magnetic layer 246. Such a columnar structure separated by a non-magnetic separator provides an exchange-reduced bond in the first magnetic layer 246. The exemplary sputtering pressure used to deposit the intermediate layer 238, the magnetic zero layer 240, and / or the magnetic layer 242 may range from about 2 to 200 mTorr, for example from about 60 mTorr to 120 mTorr.

One or more variables of the deposition process used to form each layer of the medium 200 in combination with the inclusion of a magnetic zero layer 240 between the intermediate layer 238 and the magnetic layer 242 at a predetermined level. It may be controlled to provide a magnetic layer 242 with exchange-reduced coupling and / or to provide other properties. An exemplary deposition variable may include the sputtering pressure, the concentration of oxygen level used during reactive sputtering, and the sputtering bias voltage. An exemplary sputtering bias voltage used to deposit the intermediate layer 238, the magnetic zero layer 240, and / or the magnetic 242 may range from about 5V to about 500V, for example from about 75V to 275V.

In some examples, one or more of the sputtering pressure, oxygen level concentration, and sputtering bias voltage form a corresponding layer in a magnetic recording medium that has substantially the same structure but no magnetic zero layer. May be adjusted with respect to the value used for. Magnetic recording without the magnetic zero layer, for example, due in part to the effects provided by the magnetic zero layer 240, such as increased exchange loss and / or uniformity, increased coercive force, and / or other effects. The intermediate layer 238c and / or the first magnetic layer 246 may be deposited with reduced sputtering pressure while still providing some overall recording performance level equal to or even better than the medium. For example, by using a magnetic zero layer, a first magnetic layer that includes an intermediate layer 238 formed at a higher sputtering pressure but is equal to or even larger than an exemplary medium without a magnetic zero layer 240. The overall level of exchange decoupling and / or coercive force in 246 may be given. In some examples, the sputtering pressure used to form the intermediate layer 238c may be less than about 80 mTorr and the first magnetic layer 246 may still have Hc greater than about 4700 Oe. In general, the exchange decoupling in the magnetic recording layer 242 is, despite adjusting one or more sputtering parameters in a manner that would generally reduce the exchange decoupling in the first magnetic layer 246. By including a magnetic zero layer 240 between the intermediate layer 238 and the magnetic layer 242, it may be substantially the same or even increased.

In some implementations, a magnetic zero layer 240 may be provided between the intermediate layer 238 and the magnetic layer 242 to increase the exchange-reduced coupling and / or coercive force of the first magnetic layer 246. In some examples, the magnetic zero layer 240 has less topographic roughness (surface roughness), a lower concentration of reactive oxidation, and a total amorphous separator in the first magnetic layer 246. It may allow increased separation of magnetic particles in the first magnetic layer 246, which has a smaller volume. In such an example, during sputter deposition, the first magnetic layer 246 may contain core magnetic particles having a substantially constant composition from a single sputter target, but the first magnetic layer 246. The volume of amorphous material within may be reduced by reactive oxidation as the layer grows. Such an example is an intermediate layer that allows a predetermined level of exchange decoupling within the first magnetic layer 246 using relatively low sputtering pressures (eg, sputtering pressures between about 2 mTorr and 20 mTorr). 238 may be deposited or the intermediate layer 238 may be formed from FCC + Ru. The intermediate layer 238 formed from FCC + Ru has a crystal structure of the intermediate layer 238a having a crystal structure of FCC (for example, (111) NiW, (111) NiFeW, etc.) and a low sputtering pressure (2 mTorr to 20 mTorr). Is an HCP (eg, (002) Ru, (002) RuCr, etc.) and has a low sputtering pressure (eg, 2 mTorr to 20 mTorr), and the crystal structure of the intermediate layer 238c is (eg, (002) Ru, (002) RuCr, etc.) ) HCP and high sputtering pressure (eg, between 20 mTorr and 200 mTorr) may be included. In such a case, the intermediate layer 238 is composed of an FCC layer (intermediate layer 238a) and an HCP layer (intermediate layer 238b and intermediate layer 238c).

In some cases, even if the thickness of the intermediate layer 238 is less than about 25 nm, even if the Hc-Hn of the first magnetic layer 246 is greater than about 2500 Oe and the lattice mismatch is less than about 4%. Good.

<p> The following examples illustrate one or more embodiments of the present disclosure, but do not limit the scope of the present disclosure.</p><p> Example 1 Various exemplary vertical magnetic recording media having a layered structure substantially similar to that shown in FIG. 2 were prepared and evaluated. To evaluate the effect of the magnetic zero layer ("Mo layer") between the interlayer and the magnetic recording layer, the thickness of the magnetic zero layer is 0 (ie no magnetic zero layer), about 2 angstroms, about 7 angstroms, Examples of about 16 angstroms, about 23 angstroms, and about 33 ongstroms were generated.</p><p> In each of the various examples, the bottom SUL is an amorphous FeCoCrB alloy with a thickness between about 100 and 200 angstroms; the AFC layer is a Ru alloy with a thickness between about 4 and 4 angstroms; the top SUL is a thickness. Is an amorphous FeCoCrB alloy between about 100 and 200 angstroms; the crystal seed layer is an amorphous NiW alloy between about 60 and 100 angstroms; and the columnar seed layer is about 40 to 80 angstroms thick. RuCr alloy between; columnar reduced bond layers are Ru alloys between about 60 and 100 angstroms in thickness; magnetic zero layers (different thicknesses as shown above) CoCr- (TIO)₂) Material; the bottom magnetic layer is CoCrPt- (SiO) with a thickness between about 60 and 100 angstroms.₂); The exchange blocking layer is a RuCo alloy with a thickness between about 5 and 10 angstroms; the top magnetic layer is a CoCrPt- (TIO) with a thickness between about 20 and 50 angstroms.₂) Layer, followed by a CoCrPtB layer with a thickness of about 40-80 angstroms.</p><p> 4a and 4b show the magnetic coercive force (H) for the bottom magnetic recording layer of the magnetic layer relative to the thickness of the magnetic zero layer for an exemplary medium._c), And the delta (H) between the magnetic coercive force and the nucleation magnetic field._c-H_nIt is a graph which shows the change with) respectively. As shown, the magnetic recording of Examples is compared to a medium that does not have a magnetic zero layer between the crystal intermediate layer and the magnetic recording layer (corresponding to the zero thickness of the magnetic zero layer in FIGS. 4a and 4b). H presented by the medium_cAnd H_c-H_nBoth of the values of are increased up to a layer thickness of about 7 angstroms, and then decrease in a nearly monotonous manner when the thickness of the magnetic zero layer exceeds about 7 angstroms and is increased to about 33 angstroms. H_cAnd H_c-H_nIt is illustrated that the inclusion of the magnetic zero layer improves the exchange decoupling in the magnetic recording medium of the example as compared to the magnetic recording medium of the comparative example which does not include the magnetic zero layer.</p><p> FIG. 5 shows a lattice mismatch between (002) Ru in the middle layer and (002) Co in the bottom magnetic recording layer with respect to the thickness of the magnetic zero layer for the same exemplary perpendicular recording medium of FIGS. 4a and 4b. It is a graph which shows the change of. As shown in FIG. 5, the lattice mismatch is maintained below about 4% until the thickness of the magnetic zero layer reaches about 7 angstroms, which is the case with the intermediate layer (002) Ru and the magnetic recording layer. (002) Shows a coherent interface with Co. However, when the thickness of the magnetic zero layer increases beyond about 7 angstroms, for example at thicknesses 15, 23, and 33 angstroms, the lattice mismatch increases above about 4.2 percent, which is the intermediate layer. Shows a substantially non-coherent interface between (002) Ru and (002) Co of the magnetic recording layer.</p><p> Combined with the results of FIGS. 4a and 4b, a magnetic zero structure with a coherent interface appears to increase the stress induced at the interface as an increase in lattice parameter strain under a constant Young modulus. Without being bound by any particular theory, this induced coherent stress can contribute to the improvement of exchange-reduced coupling in vertical magnetic recording media, which is shown in FIGS. 4a and 4b._cAnd H_c-H_nConsistent with the increase in. However, at a thickness of the magnetic zero layer greater than about 15 angstroms, an increase in lattice mismatch was observed with a monotonous decrease in Hc and Hc-Hn shown in FIGS. 4a and 4b, which is not coherent due to the Mo structure. It is shown that the interface reduces the exchange loss coupling in the vertical magnetic recording medium of the example. In some aspects, FIG. 5 shows, for example, that the coherent interface between (002) Ru in the CI layer and (002) Co in the perpendicular magnetic recording layer, which has the associated elastic stress, is exchanged in the perpendicular recording medium. It suggests that the binding can be improved.</p><p> In some examples, the magnetic zero layer is epitaxial between the intermediate layer and the magnetic recording layer in order to maintain a coherent interface between (002) Ru of the CI layer and (002) Co of the perpendicular magnetic recording layer. Maintain the crystal axis. FIG. 6 is a graph illustrating the difference in FWHM (full width at half maximum) of the crystal locking curve between (002) Ru in the intermediate layer and (002) Co in the bottom magnetic recording layer with respect to the thickness of the magnetic zero layer. As shown in FIG. 6, the presence of the magnetic zero layer does not substantially degrade the delta FWHM between the (002) Ru layer and the (002) Co layer. This is because the difference between the (002) Ru layer and the (002) Co layer is relatively constant except in the case where the thickness of the magnetic zero layer is about 33 angstroms.</p><p> As shown in FIG. 5, the coherent interface between the intermediate layer (Ru layer) and the magnetic layer (Co layer) can be maintained by the lattice mismatch between the two layers being less than 4%. Further, as shown in FIG. 6, the epitaxial crystal axis between the Ru layer and the Co layer has a constant FWHM delta (difference between locking curves) of about 0.35 degrees between the two layers. It can be maintained by falling below. Therefore, in the example shown, the lattice mismatch between the intermediate layer and the first magnetic layer is lower than 4%, and the constant FWHM locking curve delta between the Ru layer and the Co layer is 0.35. In combination with less than degree, it is possible to maintain an epitaxial crystal axis in which the interface between the Ru and Co layers is coherent, which corresponds to a magnetic zero thickness of less than about 11A. .. At a magnetic zero layer thickness of about 33 angstroms, the magnetic zero layer formed a non-coherent interface between the intermediate layer and the first magnetic layer, which is an epitaxial relationship between these two layers. Is lacking. The magnetic zero thickness between about 11A and about 33A can be considered as an intermediate transition region from a coherent epitaxial interface to a non-coherent non-epitaxial interface.</p><p> Example 2 In order to further evaluate the effect of including a magnetic zero layer between the intermediate layer and the magnetic recording layer, three types of exemplary magnetic recording media were prepared and evaluated. The first exemplary medium (referred to as Type A) was substantially the same as that used in Example 1, but did not have a magnetic zero layer. The second exemplary medium (referred to as type B) and the third example (referred to as type C) have substantially the same configuration as that used in Example 1, and the thickness of the magnetic zero layer is about. It was 7 angstroms. However, the steps used to prepare the Type B and Type C examples were different. Type B had the same sputtering process and disc-like structure as Type A, except for the insertion of zero magnetic force between the interlayer and magnetic layers in the Type B medium. The type C medium has a sputtering process and a disc-like structure with a type B medium, except that a different sputtering process is used for the first magnetic recording layer (see first magnetic layer 246 in FIG. 2). It was the same.</p><p> With reference to FIG. 2, a multi-step process was used for the type C medium as compared to the type B medium. For Type A and Type B media, the sputtering process of the first magnetic recording layer 246 is referred to as the first sputtering process, and for Type C media, it is referred to as a two-step or multi-step process. In the first sputtering steps of type A and type B, only one sputtering condition was applied during the deposition of the first magnetic recording layer 246. However, in the Type C multi-step process, some sputtering conditions were sequentially applied during the deposition of the first magnetic recording layer 246. For example, a lower bias voltage was applied for half the deposition duration (first half of the layer thickness) and a higher bias voltage was applied for the remaining half of the deposition duration (second half of the layer thickness). Such an example may be referred to as two-step deposition. When three different sputtering conditions are used for the first magnetic recording layer 246, this may be referred to as three-step deposition, and so on. Variable parameters for the multi-step sputtering process can be sputtering pressure, sputtering oxygen gas content, sputtering bias voltage, sputtering sublayer thickness ratio, and the like.</p><p> As shown in the graph below, the sputtering pressure used for sputtering the Ru reduced coupling layer 238c of the intermediate layer 238 in each exemplary medium was changed in each of the Type A-Type C examples. In particular, sputtering pressures of about 80, 90, 104, 120, and 140 mTorr were used. As noted above, in some cases, increasing the sputtering pressure used to form the Ru reduced coupling layer 238c of the intermediate layer 238 results in magnetic exchange reduced coupling of the magnetic layer 242 due to the induced columnar structure. Can be improved.</p><p> 7a and 7b show the magnetic coercive force (H) in terms of the sputtering pressure for forming the intermediate layer 238 for three exemplary recording media, type A-type C._c) And the delta between the magnetic coercive force and the nucleation field (H)_c-H_nIt is a graph which shows each exchange decoupling level by). As shown in FIGS. 7a and 7b, the type A medium is H as the Ru sputtering pressure decreases, as compared to the type B medium._cAnd H_c-H_nPresents a relatively rapid decline in. This indicates that the magnetic zero layer of the Type 2 disc provides an improved exchange decoupling of the medium, even when relatively lower pressures are used for the deposition of the intermediate layer.</p><p> For the purpose of evaluating the magnetic zero layer, another exemplary exchange-reduced coupling parameter, alpha, was evaluated. Alpha is equal to the magnetic coercive force divided by the difference between the magnetic coercive force and the nucleation magnetic field (ie alpha = Hc / (Hc-Hn)). The alpha may correspond to the slope of the second quadrant of the hysteresis loop. If the alpha is equal to 1, the magnetic layer may be characterized as fully exchange-decoupled. As the value of alpha increases from 1, the magnetic layers may be characterized as being exchange-bonded.</p><p> FIG. 8 is a graph illustrating the alpha values of the magnetic layer for three exemplary perpendicular recording media, type A-type C, at different sputtering pressures. As shown, the alpha value of the Type A example decreases as the Ru sputtering pressure increases, which means that the Ru layer forms an exchange-decoupled columnar structure at higher Ru pressures. Shown. However, the alpha value for the Type B example at a lower pressure, eg 80 mTorr, shows a lower alpha value than even the highest sputtering pressure of the Type A example. Such results may indicate that the magnetic zero layer induced increased exchange decoupling in the type B example compared to the type A example.</p><p> In some cases, due to the increased exchange decoupling seen in the Type B example compared to the Type A example due to the inclusion of a magnetic zero layer, the exchange decoupling is one or more during the fabrication of the magnetic medium. It may be adapted to achieve the target exchange decoupling (and / or other magnetic recording parameters) in the magnetic layer by controlling the process parameters. Exemplary process parameters that can be adjusted to achieve the target exchange decoupling may include sputtering pressure, reactive oxygen gas concentration used for reactive sputtering, and sputtering bias voltage.</p><p> 9a and 9b are graphs illustrating magnetic core width (WR_WDT) and magnetic writing width (WPE_AVG) for three exemplary perpendicular recording media, type A-type C, at various sputtering pressures, respectively. Is. The magnetic writing width is equal to the magnetic core width plus the erasing band. As shown, the narrower magnetic core width and magnetic write width provided by the magnetic zero layer may allow for increased surface recording density capability (ADC).</p><p> 10a and 10b show on-track bit error rates (PE_EFL) and squeezed off-track bit error rates (OTC_EFL) for three exemplary perpendicular recording media, type A-type C, at various sputtering pressures. It is a graph which shows each. As mentioned above, in some cases, increasing the sputtering pressure used to form the intermediate layer can improve the magnetic exchange decoupling of the magnetic layer due to the induced columnar structure. Such an increase can result in improved bit error rate performance. Instead of relying on higher sputtering pressures to deposit the intermediate layer to provide increased exchange decoupling, the inserted magnetic zero layer increases exchange decoupling at lower sputtering pressures. Thus, by incorporating a magnetic zero layer, such as in Type B and Type C media, the on-track bit error rate and on-track bit error rate at lower sputtering pressures and, for example, as compared to the Type A example without the magnetic zero layer. The squeezed track off-track bit error rate can be optimized.</p><p> FIG. 11 is a graph illustrating on-track bit error rates (PE + 10LnWPE / TP) normalized by track pitch for three exemplary perpendicular recording media, Type A-Type C, at various sputtering pressures. Is. As shown, the examples with a magnetic zero layer (Type B and Type C) demonstrated on-track bit error rates standardized by improved track pitch compared to the Type A example. In addition, the Type C example demonstrated an on-track bit error rate standardized by the improved track pitch compared to the Type B example.</p><p> FIG. 12 is a graph illustrating media signal to noise ratio (ESMNR) for three exemplary perpendicular recording media, Type A-Type C, at various sputtering pressures. As shown, the increase in media signal-to-noise ratio from the combination of the presence of a magnetic zero layer (type B and type C examples) and the adjustment of process parameters to control exchange decoupling (type C example) It matches the above bit error rate performance.</p><p> 13a and 13b show the calculated areal density capacity (ADC cal) and the measured areal density capacity for three exemplary vertical recording media, type A-type C, at various sputtering pressures. It is a graph which illustrates (ADC-747) respectively. The calculated areal density capacity was calculated as equal to x (1-0.1 (PE_EFL + 5)) / WPE. In the equation, x is equal to kilobits per square inch, PE_EFL is equal to the on-track bit error rate, and WPE is equal to the magnetic write width.</p><p> As shown in FIGS. 13a and 13b, the combination of the presence of the magnetic zero layer (type B and type C examples) and process parameter adjustment (type C example) is calculated as compared to the type A example. The surface recording density per measured value and measured value was increased.</p><p> This disclosure includes several numerical ranges that are practicable throughout the disclosed numerical ranges. The above description of the various embodiments has been presented for purposes of illustration and description, not for limitation. The disclosed embodiments are not intended to be exhaustive or limited to embodiments that disclose possible realizations. A large number of modifications and modifications are possible in light of the above teachings.</p>

100, 200 magnetic recording medium, 110, 228 substrate, 120, 230 soft magnetic base layer, 130, 238 crystal orientation intermediate layer, 140, 240 magnetic zero layer, 150, 242 magnetic layer.