Magnetoresistive element and magnetic random-access memory

A magneto-resistive effect element and magnetic random access memory

0001The embodiment of the present invention is related with a magneto-resistive effect element and magnetic random access memory.

0002The solid magnetic memory various type is proposed from the former. in recent years, the magnetic random access memory (MRAM:Magnetic*Random*Access*Memory) using the magneto-resistive effect element which shows the giant magnetoresistance (GMR:Giant*Magneto*Resistive) effect is proposed -- especially Attentions have gathered for the magnetic random access memory using the ferromagnetic tunnel junction which shows the tunnel magnetic resistance (TMR:Tunneling*Magneto*Resistive) effect.

0003the MTJ (Magnetic*Tunnel*Junction) element of a ferromagnetic tunnel junction -- mainly -- [ 1st / the / ferromagnetic layer / insulating layer / ] -- it comprises three layer membranes of the ferromagnetic layer of two. And at the time of read-out, an insulating layer is tunneled and current flows. In this case, the resistance of a ferromagnetic tunnel junction changes according to cosine of the relative angle of magnetization of the 1st and 2nd ferromagnetic layers. For example, the resistance of a ferromagnetic tunnel junction takes the local maximum at the time of the local minimum and anti-parallel (reverse direction), when direction of magnetization of the 1st and 2nd ferromagnetic layers is parallel (the same direction). This is called the TMR effect mentioned above. Change of the resistance by this TMR effect may exceed 300% in room temperature.

0004In the magnetic memory unit which contains the MTJ element of a ferromagnetic tunnel junction as a memory cell, it considers that at least one ferromagnetic layer is a standard layer, and the magnetization direction is fixed, and let other ferromagnetic layers be recording layers. In this cell, information is memorized because arrangement of magnetization of a standard layer and a recording layer matches "0" or "1" of 2 Progress information to a parallel state or an anti-parallel state. Arrangement of magnetization of a standard layer and a recording layer may match with "1" or "0" to a parallel state or an anti-parallel state. Conventionally, the method (henceforth a current magnetic field write-in method) which reverses magnetization of a recording layer by the magnetic field which the writing of recorded information sends current through the write-in wiring independently provided to this cell, and occurs was taken. However, in a current magnetic field write-in method, the memory cell followed on becoming detailed, current required for writing increased, and there was a problem that large scale-ization became difficult.

0005In recent years, the method (henceforth a spin torque write-in method) which reverses magnetization of a recording layer by the spin torque poured in from a standard layer was proposed by energizing directly for a MTJ element as a reversal method of a magnetic body which changes to a current magnetic field write-in method (for example, refer to patent documents 1). Current required for writing decreases and a spin torque write-in method has the feature that large-scale-izing is easy, so that a memory cell is made detailed. Information read-out from a memory cell sends current through a ferromagnetic tunnel junction, and is performed by detecting the resistance change by the TMR effect.

0006A magnetic memory comprises arranging a majority of such memory cells. A switching transistor is arranged to each memory cell like DRAM, and a peripheral circuit is incorporated and it is constituted by actual composition so that arbitrary cells can be chosen. As the spin torque write-in method was mentioned above, it is suitable for reducing current required for information writing, but in order to reverse magnetization, the current which flows bidirectionally is required and there is a problem that the number of peripheral circuits required for a drive increases.

0007In order to actually realize a bulk memory, it is because it is necessary to also reduce peripheral circuit area other than a memory cell portion. It is sending current through one way and changing the size and pulse width of current as a method of solving this problem, The method which causes the magnetization reversal to the direction respectively corresponding to information "0" and "1" using the difference in the spin torque write-in current in each condition-izing is proposed (see the patent documents 2 and 3). When using such art, it is a parameter with required for the determination of the magnetization reversal direction changing pulse width.

0008Therefore, in order to perform stable writing without incorrect writing, it is necessary to lengthen pulse width enough at the time of the information writing to the direction corresponding to one of information "0" and "1." This poses a problem from a viewpoint of high-speed operation of a memory. Supposing it coincides the integral multiple and pulse width of a precession movement of a magnetic body which are indicated in patent documents 2, control with pulse width precise to each element in a memory cell is required. However, in the actual memory cell, since delay by the variation in wiring capacity, the variation of a pulse shape, etc. existed, generally as for controlling the pulse width between elements with sufficient accuracy, the difficult problem existed. For this reason, stable writing without incorrect writing was not able to be performed.

<p num="0009"><patcit num="1"><text>U.S. Pat. No. 6,256,223 specification</text></patcit><patcit num="2"><text>JP,2009-152258,A</text></patcit><patcit num="3"><text>U.S. patent application public presentation of/[ 2009th ] No. 0213642 specification</text></patcit></p>

<p num="0010">This embodiment is made in consideration of the above-mentioned situation, and aims at providing the magneto-resistive effect element and magnetic random access memory which can perform the stable writing which does not have incorrect writing using unidirectional current.</p>

<p num="0011">magnetization of the magneto-resistive effect element by this embodiment receives a film surface -- abbreviated -- the perpendicular and variable 1st a little more than magnetic layer, magnetization receives a film surface -- abbreviated -- the 1st non-magnetic layer provided between the perpendicular and eternal 2nd a little more than magnetic layer, and the above-mentioned 1st a little more than magnetic layer and the above-mentioned 2nd a little more than magnetic layer, The 3rd a little more than magnetic layer which generates a revolving magnetic field by being provided in the side the 1st above-mentioned non-magnetic layer and opposite to to the above-mentioned 2nd a little more than magnetic layer, having magnetization almost parallel to a film surface, and pouring in the electron by which spin polarization was carried out, The 2nd non-magnetic layer provided between the above-mentioned 2nd a little more than magnetic layer and the above-mentioned 3rd a little more than magnetic layer, Preparation, The 1st current is sent in one direction of [ of the directions which go to the above-mentioned 3rd a little more than magnetic layer via the above-mentioned 2nd a little more than magnetic layer from the direction which goes to the above-mentioned 1st a little more than magnetic layer via the above-mentioned 2nd a little more than magnetic layer from the above-mentioned 3rd a little more than magnetic layer, and the above-mentioned 1st a little more than magnetic layer ]. Magnetization of the above-mentioned 1st a little more than magnetic layer can be reversed by the above-mentioned revolving magnetic field which occurs from the above-mentioned 3rd a little more than magnetic layer, Magnetization of the above-mentioned 1st a little more than magnetic layer is characterized by the ability to be reversed in the different direction from the case where the 1st above-mentioned current is sent by the electron which sent the 2nd current that has different current density from the 1st above-mentioned current in above-mentioned one direction and in which spin polarization was carried out by the above-mentioned 2nd a little more than magnetic layer.</p>

0012<figref num="1">Drawing 1 (a) and 1 (b) are the figures showing the resonance phenomena by the high frequency magnetic field of a magnetic body.</figref><figref num="2">The graph which shows the number dependence of frequency of a magnetization perpendicular ingredient.</figref><figref num="3">The figure showing the simulation result of a magnetization state at the time of the resonance magnetic field writing by a microwave magnetic field.</figref><figref num="4">The figure showing the simulation result of a magnetization state when the circumference microwave magnetic field of a clock is impressed.</figref><figref num="5">The sectional view showing the magneto-resistive effect element of a 1st embodiment.</figref><figref num="6">The mimetic diagram at the time of impression of the microwave magnetic field in the magneto-resistive effect element of a 1st embodiment.</figref><figref num="7">The figure showing the current dependence of the rotation frequency of a magnetic rotation layer.</figref><figref num="8">Drawing 8 (a) and 8 (b) are figures which illustrate the magnetization reversal to an anti-parallel state from a parallel state in the magneto-resistive effect element of a 1st embodiment.</figref><figref num="9">Drawing 9 (a) and 9 (b) are figures which illustrate the magnetization reversal to a parallel state from an anti-parallel state in the magneto-resistive effect element of a 1st embodiment.</figref><figref num="10">Drawing 10 (a) and 10 (b) are the figures showing the simulation result of magnetization reversal of the magneto-resistive effect element of a 1st embodiment.</figref><figref num="11">11 (b) is Drawing 11 (a) and a figure showing the simulation result of magnetization reversal of the magneto-resistive effect element of a 1st embodiment.</figref><figref num="12">The sectional view of the magneto-resistive effect element by a 2nd embodiment.</figref><figref num="13">The sectional view of the magneto-resistive effect element by the modification of a 2nd embodiment.</figref><figref num="14">The sectional view of the magneto-resistive effect element by a 3rd embodiment.</figref><figref num="15">The sectional view of the magneto-resistive effect element by a 4th embodiment.</figref><figref num="16">The sectional view of the magneto-resistive effect element by the modification of a 4th embodiment.</figref><figref num="17">The circuit diagram showing MRAM by a 5th embodiment.</figref><figref num="18">The circuit diagram showing MRAM of a 6th embodiment.</figref>

0013Before describing each embodiment, the principle of the resonance magnetic field writing used for each embodiment is explained.

0014In the magneto-resistive effect element by one embodiment, In order for there to be no incorrect writing and to perform stably the magnetization reversal writing to the direction corresponding to information "0" and "1" using the current of one direction, not only a spin torque write-in method but the resonance magnetic field write-in method by impressing a microwave magnetic field is used.

0015Generally, the magnetic body has a microwave magnetic field and the resonating peculiar resonant frequency according to anisotropic energy or saturation magnetization. If the microwave magnetic field corresponding to resonant frequency is made to act in the direction parallel to a film surface to the magnetic body which has magnetization (henceforth perpendicular magnetization) of a direction perpendicular to a film surface, resonance phenomena will arise, and perpendicular magnetization inclines in the direction quickly parallel to a film surface, and begins a precession movement.<br />A film surface means the upper surface of a magnetic body. Saturation magnetization Ms is 800 emu(s)/cc, and anisotropic energy Ku is 1.0x10.^７It has perpendicular magnetization also for an erg/cc magnetic parameter suddenly [ both ], and prepares the magnetic recording layer of 30 nm in diameter disk shape. It has a surface of revolution in the direction parallel to the film surface of this magnetic recording layer, and when it sees from the upper part, the case where the microwave magnetic field which rotates in the direction of the circumference of an anti-clock is impressed to the above-mentioned magnetic recording layer is considered. In this case, the result of having done simulation calculation of the magnetization ingredient perpendicular to the film surface of a magnetic recording layer which can be set is shown in Drawing 1 (a) and 1 (b), respectively. Drawing 1 (a) and 1 (b) are simulation calculation results in case the rotation frequency (only henceforth frequency) of a microwave magnetic field is 3 GHz and 6 GHz, respectively and amplitude is the same 200Oe. In Drawing 1 (a) and each of 1 (b), a horizontal axis shows magnetization and a vertical axis shows magnetization ingredient Mz perpendicular to the film surface in a magnetic recording layer. In Drawing 1 (a) and 1 (b), that the value of Mz is 1.0 shows the case where direction of magnetization of a magnetic recording layer is upward, and that the value of Mz is -1.0 shows the case where direction of magnetization of a magnetic recording layer is downward. In this simulation calculation, as shown in Drawing 1 (a), when the frequency of the microwave magnetic field impressed is 3 GHz, direction of magnetization of a magnetic recording layer serves as the same facing down as the initial state before a microwave magnetic field is impressed, and direction of magnetization does not change almost. On the other hand, when the frequency of the microwave magnetic field impressed is 6 GHz, it turns out that magnetization of the magnetic recording layer was in the resonance state clearly, and magnetization leans in the parallel direction from a direction perpendicular to a film surface.

0016Next, the frequency dependence of a microwave magnetic field about the minimum of magnetization ingredient Mz of a direction perpendicular to a film surface acquired by changing the frequency of a microwave magnetic field is shown in Drawing 2. Here, a microwave magnetic field is impressed, magnetization is made into a resonance state, and the absolute value of magnetization ingredient Mz perpendicular to a film surface when magnetization inclines most is meant as the minimum of magnetization ingredient Mz of a direction perpendicular to a film surface. Drawing 1 (a) and 1 (b) show that resonance phenomena arise at nearly 6 GHz, and magnetization inclines about this magnetic recording layer. important one can produce reversal of magnetization here, if magnetization ingredient Mz perpendicular to a film surface crosses zero by a microwave magnetic field (i.e., if it just changes from negative or negative) -- a thing meaning is carried out. [ positive to ]

0017Saturation magnetization Ms is 500 emu(s)/cc, and anisotropic energy Ku is 2.0x10.^６The magnetic recording layer which has perpendicular magnetization of erg/cc is prepared. And the simulation result of the time dependency of magnetization at the time of impressing the microwave magnetic field which has a surface of revolution in the direction parallel to the film surface of this magnetic recording layer is shown in Drawing 3. direction of magnetization of the magnetic recording layer before impressing a microwave magnetic field in this simulation -- a film surface -- abbreviated -- it is downward and microwave magnetic fields are perpendicular and a revolving magnetic field which rotates counterclockwise when a magnetic recording layer is seen from a top. Drawing 3 carries out vector resolution to an ingredient (perpendicular magnetization ingredient) perpendicular to a film surface, and an ingredient (parallel magnetization ingredient) parallel to a film surface, and shows magnetization. It is graph g about a perpendicular magnetization ingredient._１It is come out and shown and is graph g about a parallel magnetization ingredient._２It is come out and shown. If a microwave magnetic field is impressed, a parallel magnetization ingredient starts a precession movement clearly, a perpendicular magnetization ingredient inclines with time, and the numerals of a perpendicular magnetization ingredient just change from negative by about 1500 psec, namely, the direction of magnetization changes upward from facing down, and it is shown that reversal of magnetization took place. As explained above, when impressing the microwave magnetic field which has the frequency (resonant frequency) which sympathizes with magnetization of a magnetic recording layer in the magnetic recording layer which has perpendicular magnetization, causing reversal of magnetization was shown.

0018In resonance magnetic field writing, an important point is that the reversal direction of magnetization of a magnetic recording layer and the hand of cut of a microwave magnetic field correspond to 1 to 1. The result of having done simulation calculation of the time dependency of magnetization at the time of carrying out the hand of cut of a microwave magnetic field clockwise on the same conditions as the simulation shown in Drawing 3 is shown in Drawing 4. As shown in Drawing 4, it is a perpendicular magnetization ingredient (graph g) only at having made the hand of cut reverse._１it is come out and shown -- hardly changing -- a parallel magnetization ingredient (graph g)_２It is come out and shown. Vibrating became clear. If the above is summarized and the microwave magnetic field which has predetermined rotation frequency and predetermined hand of cut to a magnetic recording layer will be impressed, it is possible to reverse magnetization of a magnetic recording layer towards desired. To a magnetic storage layer, the revolving magnetic field corresponding to resonant frequency can be impressed, and the magnetic field is not restricted to a microwave magnetic field.

0019With reference to drawings, the embodiment of the present invention is described below.

0020(A 1st embodiment)<br />The magneto-resistive effect element by a 1st embodiment is shown in Drawing 5. Magnetic recording layer 12 variable [ element / 1 / of this embodiment / magneto-resistive effect ] in the magnetization direction, Tunnel barrier layer 14, magnetism reference layer 16 to which the magnetization direction is being fixed substantially, spacer layer 18, and magnetic rotation layer 20 are provided with the lamination structure laminated in the lamination structure laminated in this order, or reverse order.

0021magnetic recording layer 12 -- the direction of magnetization -- a film surface -- abbreviated -- it is perpendicular, and when current energizes for magneto-resistive effect element 1, it has a ferromagnetic layer which can make variable direction of magnetization before and behind energization. magnetism reference layer 16 -- the direction of magnetization -- a film surface -- abbreviated -- even if it is perpendicular and current energizes for magneto-resistive effect element 1, direction of magnetization before and behind energization has a ferromagnetic layer which becomes eternal. In this embodiment, direction of magnetization of magnetism reference layer 16 serves as facing down, as shown in Drawing 5. The direction of magnetization is almost parallel to a film surface, and when current energizes for magneto-resistive effect element 1, as for magnetic rotation layer 20, magnetization has a ferromagnetic layer which magnetization rotates in an almost parallel side.

0022An electron is made to tunnel, and a desired magnetoresistance change is obtained, for example, tunnel barrier layer 14 consists of the oxide or nitriding thing containing the element of either Mg, aluminum, Ti or Hf. Spacer layer 18 is a non-magnetic layer which penetrates the electron which carried out spin polarization, and can use the metal which consists only of an element of either Cu, Au, Ru or Ag, for example, or the alloy containing these at least one elements as the material. The oxide or nitriding thing which contains the element of either Mg, aluminum, Ti or Hf, for example may be used.

0023In order to record information in the magnetization direction of magnetic recording layer 12, in magneto-resistive effect element 1 of this embodiment, it is necessary to form with a magnetic body with sufficiently big perpendicular magnetic anisotropy, and to secure the stability over heat turbulence. Therefore, as for the magnetic material optimal as magnetic recording layer 12, it is desirable that it is the rule alloy or irregular alloy containing at least one element in Fe, Co, and nickel and at least one element in Cr, Pt, Pd, and Ta. For example, L1 in which magnetic recording layer 12 contains at least one element among at least one element in Fe, Co, and nickel, and Pt and Pd_０It is preferred to be formed with the magnetic body which has a model crystal structure. As for magnetic recording layer 12, it is preferred to be formed with the magnetic body which has a hexagonal type crystal structure which contains at least one element among at least one element in Fe, Co, and nickel, Cr and Pt, Pd, and Ta. As magnetic recording layer 12, it may be formed with the rule alloy or irregular alloy which contains one or more elements among rare earth metal Sm, Gd, Tb, and Dy.

0024According to this embodiment, magnetic rotation layer 20 is used as a source of a microwave magnetic field. If the electron by which spin polarization was carried out is poured in, when the left screw progresses to the direction of an electronic spin which was poured into magnetic rotation layer 20 and which carried out spin polarization, magnetization of magnetic rotation layer 20 will rotate this magnetic rotation layer 20 in the direction which the left screw rotates. When it writes in magnetic rotation layer 20 via tunnel barrier layer 14, magnetism reference layer 16, and spacer layer 18 from magnetic recording layer 12 and current is sent in this embodiment, That is, the case where an electron is passed from magnetic rotation layer 20 to magnetic recording layer 12 via spacer layer 18, magnetism reference layer 16, and tunnel barrier layer 14 is considered. In this case, the electron which passed magnetic rotation layer 20 since direction of magnetization of magnetism reference layer 16 had become facing down, Spin polarization is carried out by magnetism reference layer 16, and it separates into the electron which has a spin of the same direction as magnetization of magnetism reference layer 16 and by which spin polarization was carried out, and the electron which have a spin of direction contrary to magnetization of magnetism reference layer 16 and by which spin polarization was carried out. The electron which has a spin of the same direction as magnetization of magnetism reference layer 16 and by which spin polarization was carried out passes magnetism reference layer 16. However, it is reflected by magnetism reference layer 16, the electron which has a spin of direction contrary to magnetization of magnetism reference layer 16 and by which spin polarization was carried out is poured into magnetic rotation layer 20 via spacer layer 18, and magnetization of magnetic rotation layer 20 begins to rotate it. Since the direction of an electron by which the hand of cut at this time was poured into magnetic rotation layer 20 and which carried out spin polarization is upward, magnetization of magnetic rotation layer 20 serves as a clockwise rotation, when magnetic rotation layer 20 is seen from the upper part.

0025If current is sent through an above-mentioned case and an opposite direction in this embodiment (i.e., if an electron is passed in magnetic rotation layer 20 via magnetic recording layer 12, tunnel barrier layer 14, magnetism reference layer 16, and spacer layer 18) The electron which is poured into magnetic rotation layer 20 and which carried out spin polarization has the same downward spin as magnetization of magnetism reference layer 16. For this reason, magnetization of magnetic rotation layer 20 rotates counterclockwise, when magnetic rotation layer 20 is seen from the upper part.

0026Signs that the microwave magnetic field which occurs when magnetization of magnetic rotation layer 20 rotates is impressed to magnetic recording layer 12 are shown in Drawing 6. Rotation frequency f at the time of pouring in the electron which carried out spin polarization to magnetic rotation layer 20_iIt is expressed with the following equations by solving Is and a LLG (Landau-Lifshitz-Gilbert) equation (for example, M.*Mansuripur, *J.*Appl.*Phys., *63:5809, *1988 reference).<br /><maths num="1"><img file="WO2012036282A1_D0001.tif" /></maths>The Dirac constant whose gamma is the value by which a gyroscope magnetic constant and alpha broke the dumping constant by 2 pi, and h bar broke Planck constant h here, The magnetic field (for example, leak magnetic field from a magnetism reference layer) and Hk by which the current density and P into which as for e the amount of electric matter and Ms flow into through saturation magnetization, t flows into through the film thickness of a magnetic rotation layer, and J flows through a magnetic rotation layer are impressed to the side highest degree, and Hz is impressed to magnetic rotation layer 20 express the anisotropy field of magnetic rotation layer 20.

0027In this embodiment, the current density dependency of the rotation frequency at the time of sending current through magnetic rotation layer 20 (age difference frequency) searched for using the upper type is shown in Drawing 7. Here, rotation frequency makes negative the case where make positive the case where it rotates clockwise and it rotates counterclockwise, when magnetic rotation layer 20 is seen from a top, Current density J makes negative the case where make positive the direction which sends current through magnetic rotation layer 20 via tunnel barrier layer 14, magnetism reference layer 16, and spacer layer 18 from magnetic recording layer 12, and it passes to an opposite direction. As shown in Drawing 7, it turns out that the rotation frequency of magnetic rotation layer 20 can be adjusted by adjusting the magnetic parameter (for example, saturation magnetization Ms or side extreme P) of current density J and magnetic rotation layer 20. For example, the absolute value of rotation frequency can be raised by being able to raise the absolute value of rotation frequency by enlarging the absolute value of current density J, and enlarging side extreme P, if current density J is constant. If the rotation frequency of important one of magnetic rotation layer 20 in desired current density J corresponds with the resonant frequency of magnetic recording layer 12 here, If it becomes possible to perform resonance magnetic field writing as stated previously, and current density is changed and rotation frequency is shifted from the resonant frequency of magnetic recording layer 12, it will be that resonance magnetic field writing does not take place. If this character is used, it will become possible to make it reversed in the magnetization direction of the magnetic recording layer corresponding to information "0" and "1" using the current of one way which is the feature of one embodiment of the present invention.

0028The suitable value of the resonant frequency of a magnetic recording layer is calculated by the dependence of a heat turbulence index and resonant frequency. The resonant frequency of a magnetic recording layer is denoted by the formula of the next Kittel.<br /><maths num="2"><img file="WO2012036282A1_D0002.tif" /></maths>It is here and f is resonant frequency and K._uAnisotropy energy of Is the magnetic recording layer, M_sThe saturation magnetization of Is the magnetic recording layer and gamma are a gyroscope constant and K._ueffIt is the effective anisotropy energy in consideration of Is the demagnetizing field.

0029On the other hand, a heat turbulence index is effective anisotropy energy K._ueffIt is expressed with a product with the volume of a magneto-resistive effect element. In consideration of the variation in a magneto-resistive effect element, it is necessary to set up a heat turbulence index so that the unusual reversal by heat may not take place, and in a magnetic memory, it is preferred that a heat turbulence index is 30 to 120. The ranges of the suitable resonant frequency of a magnetic recording layer for resonance magnetic field writing in case a heat turbulence index is 30 to 120 to take place are 2 GHz - 40 GHz.

0030A magnetic rotation layer has a preferred field inner-magnet-ized film with large Polarization rate, in order to improve rotation efficiency, and it is at least one element in Fe, Co, and nickel, It is preferred to use the alloy (for example, CoFe, Fe, CoFeNi) etc. which use the magnetic body containing at least one element in B, Si, and C, or contain at least one element in Fe, Co, and nickel.

0031In order that a magnetism reference layer may perform stable spin pouring to a magnetic recording layer and a magnetic rotation layer, In order to improve rotation efficiency, it is desirable to have big perpendicular magnetic anisotropy, and it is preferred to use a magnetic body with the perpendicular magnetic anisotropy containing at least one element in Fe, Co, and nickel and at least one element in Cr, Ta, Pt, and Pd. A magnetic body with the perpendicular magnetic anisotropy containing at least one element of rare earth elements, such as Tb, Dy, Gd, and Ho, and at least one element in Fe, Co, and nickel may be used. The magnetic body of the magnetism reference layer mentioned above to the magnetic storage layer and the magnetic rotation layer since it was required for Polarization rate to be large, The magnetic body of at least one element in Fe, Co, and nickel, B, Si, the magnetism reference layer of the lamination structural form on which the magnetic body containing at least one element of C was made to laminate, or the above quoted magnetism reference layer, The magnetism reference layer of the lamination structural form on which the alloy (for example, CoFe, Fe, CoFeNi) containing at least one element in Fe, Co, and nickel was made to laminate may be used.

0032Magneto-resistive effect element 1 of this embodiment has the feature in having two different writing mechanisms which causes reversal of magnetization in magnetic recording layer 12. When one is written in magnetic rotation layer 20 via tunnel barrier layer 14, magnetism reference layer 16, and spacer layer 18 from magnetic recording layer 12 and current is sent, It is the spin pouring writing by the electron which carried out spin polarization from magnetism reference layer 16 being poured into magnetic recording layer 12 via tunnel barrier layer 14. By pouring into magnetic rotation layer 20 the electron which was reflected by magnetism reference layer 16 and which carried out spin polarization via spacer layer 18, other one is the resonance magnetic field writing by the impression to magnetic recording layer 12 of the microwave magnetic field which occurs from magnetic rotation layer 20. This resonance magnetic field writing is written in magnetization of the same direction as the direction where the left screw advances, when the left screw rotates to the hand of cut of the microwave magnetic field impressed to magnetic recording layer 12. If an element design is performed so that the reversal directions of spin pouring writing and resonance magnetic field writing may differ and the reversal current values in each writing mechanism may differ, it will become possible to make it reversed by sending the current of one way of a different current value in the magnetization direction corresponding to information "0" and "1."

0033Especially about resonance magnetic field writing, as mentioned above, magnetic parameters, such as magnetization of magnetic rotation layer 20 and side extreme P, are changed, A current value required for resonance magnetic field writing can be changed free, and direction of magnetism reference layer 16 is made reverse about the hand of cut of magnetization, or be shown in a 3rd embodiment mentioned below, By using an antiferromagnetism joint film (Synthetic*Anti-Ferromagnetic*Coupling) as magnetic rotation layer 20, it becomes possible to change.

0034The magnetization direction of magnetic recording layer 12 to the magnetization direction of magnetism reference layer 16 in magneto-resistive effect element 1 of this embodiment explains the case from a parallel state to an anti-parallel state where magnetization reversal is carried out, with reference to Drawing 8 (a) and 8 (b). In Drawing 8 (a), the magnetization direction of magnetic recording layer 12 and magnetism reference layer 16 is parallel, and it makes it into facing down. In this state, rotation frequency is equal to the resonant frequency of magnetic recording layer 12, Or the 1st write-in current which is the current density in which magnetic rotation layer 20 generates the micro magnetic field which becomes near the resonant frequency is sent through magnetic rotation layer 20 via tunnel barrier layer 14, magnetism reference layer 16, and spacer layer 18 from magnetic recording layer 12. In this case, spin transfer torque by the electron which spin polarization of the 1st write-in current is carried out by magnetism reference layer 16, and has a spin of the same direction as magnetization of magnetism reference layer 16 acting on magnetic recording layer 12, It is a current value which becomes smaller than the reversal torque which arises in magnetic recording layer 12 by a resonance magnetic field. For this reason, even if it sends the 1st write-in current, spin pouring writing does not take place but resonance magnetic field writing produces it. Thereby, the magnetization direction of magnetic recording layer 12 to the magnetization direction of magnetism reference layer 16 changes with resonance magnetic field writing from a parallel state to an anti-parallel state (Drawing 8 (b)). That is, reversal of magnetization takes place.

0035On the other hand, the magnetization direction of magnetic recording layer 12 to the magnetization direction of magnetism reference layer 16 in magneto-resistive effect element 1 of this embodiment explains the case from an anti-parallel state to a parallel state where magnetization reversal is carried out, with reference to Drawing 9 (a) and 9 (b). In Drawing 9 (a), the magnetization directions of magnetic recording layer 12 and magnetism reference layer 16 are anti-parallel, and it makes the magnetization direction of magnetic recording layer 12 into facing up. The 2nd write-in current is sent in this state. This 2nd write-in current is chosen so that the rotation frequency of the microwave magnetic field which occurs from magnetic rotation layer 20 by this current may shift from the resonant frequency of magnetic recording layer 12. For this reason, even if it sends the 2nd write-in current, resonance magnetic field writing does not take place. However, the electron which spin polarization is carried out [ an electron ] by magnetism reference layer 16, and has a spin of the same direction as magnetization of magnetism reference layer 16 by it and which carried out spin polarization is poured into magnetic recording layer 12, and the 2nd write-in current serves as a current value which spin pouring reversal produces by this. The magnetization direction of magnetic recording layer 12 to the magnetization direction of magnetism reference layer 16 changes with these spin pouring reversal from an anti-parallel state to a parallel state (Drawing 9 (b)). That is, reversal of magnetization takes place. Liking to be careful is changing the magnetic parameter of magnetic rotation layer 20 or magnetic recording layer 12, and it can change the frequency and resonant frequency of a microwave magnetic field here.

0036Next, magneto-resistive effect element 1 of this embodiment is made into a model, and the write-in result using the one-way current calculated by the LLG simulation is shown in Drawing 10 (a) and 10 (b). The current density of Drawing 10 (a) is 2MA/cm.^２The current density of Drawing 10 (b) is 4MA/cm.^２The of simulation result is shown, respectively. The group of Drawing 10 (a) and the arrow in each upper and lower sides of 10 (b) is a group which shows direction of magnetization of magnetism reference layer 16 and magnetic recording layer 12. In each class, the upper arrow shows direction of magnetization of magnetism reference layer 16, and shows direction of magnetization of a lower arrow of magnetic recording layer 12. As shown in Drawing 10 (a) and 10 (b), it is the current density of 2MA/cm by spin pouring writing.^２The magnetization reversal to a parallel state from a In anti parallel state arises, and it is the current density of 4MA/cm by resonance magnetic field writing.^２It is clear that came out and the magnetization reversal to an anti-parallel state has arisen from the parallel state. It is although the reversal torque by resonance magnetic field writing and the reversal torque by spin pouring writing work conversely mutually in the middle of writing and direction of magnetization of a magnetic recording layer rocks in Drawing 10 (b), The direction of the reversal torque by steps and resonance magnetic field writing wins, and resonance magnetic field writing is performed. In magneto-resistive effect element 1 of this embodiment, it was shown that it is possible to make it reversed by changing the current density of the current of one way in the magnetization direction corresponding to information "0" and "1." Therefore, the stable writing where precise control of pulse width, etc. become unnecessary and which does not have incorrect writing can be performed.

0037Although the magnetization direction of magnetism reference layer 16 was made into facing down on the drawing as an example in Drawing 10 (a) and 10 (b), while making reverse the magnetization direction of magnetism reference layer 16 to make facing up, even when direction of the current sent through a magneto-resistive effect element is also made reverse, it is possible to acquire the same effect.

0038Although current required for spin inrush current writing showed the simulation result in the case of being small by Drawing 10 (a) and 10 (b) compared with resonance magnetic field writing, it is possible by changing the magnetic parameter of a magnetic rotation layer to lower current required for resonance magnetic field writing. (1) The rotation frequency of the magnetic rotation layer to the current density impressed as the formula showed is proportional to gyroscope magnetic constant gamma of a magnetic rotation layer, and is dumping constant alpha, Polarization rateP, and saturation magnetization M._sIt is inversely proportional to film thickness t. Therefore, it is optimizing the magnetic parameter of a magnetic rotation layer and making it the rotation frequency of a magnetic rotation layer reach the resonant frequency grade of a magnetic recording layer with current smaller than current density required for spin pouring writing, Current required for resonance magnetic field writing can be lowered rather than current required for spin pouring writing.

0039The magnetic parameter of the magnetic rotation layer calculated by the LLG simulation to Drawing 11 (a) and 11 (b) is optimized, and the write-in result using one-way current when the current density of resonance magnetic field writing is low is shown. As shown in Drawing 11 (a) and 11 (b), it is the current density of 1.6MA/cm by resonance magnetic field writing.^２It comes out, the magnetization reversal to an anti-parallel state from a parallel state arises, and it is the current density of 2.5MA/cm by spin inrush current writing.^２Even when it is clear from a In anti parallel state that the magnetization reversal to a parallel state has arisen and current density required for resonance magnetic field writing is lower than the current density of spin inrush current writing, it sets for magneto-resistive effect element 1 of this embodiment, It was shown that it is possible to make it reversed by changing the current density of the current of one way in the magnetization direction corresponding to information "0" and "1." The way when the current density of resonance magnetic field writing is lower than spin pouring write-in current density can make small the write-in current of a magneto-resistive effect element compared with that case of being opposite.

0040As explained above, according to this embodiment, the possible magneto-resistive effect element of performing the stable writing which does not have incorrect writing using unidirectional current can be provided.

0041(A 2nd embodiment)<br />Generally, with the magneto-resistive effect element using the magnetic film (perpendicular magnetization film) which has perpendicular magnetization, the leak magnetic field from a magnetism reference layer acts on a magnetic recording layer, and the stability of information "0" and "1" becomes asymmetrical. For this reason, the magneto-resistive effect element by a 2nd embodiment has the composition of having provided the magnetic field adjustment layer with magnetization of a magnetism reference layer, and magnetization of an opposite direction, in order to reduce the influence of the leak magnetic field from a magnetism reference layer. The magneto-resistive effect element of this 2nd embodiment is shown in Drawing 12. In the magneto-resistive effect element of a 1st embodiment shown in Drawing 5, magneto-resistive effect element 1 of this 2nd embodiment has the composition of having provided magnetic field adjustment layer 10 in the side tunnel barrier layer 14 of magnetic recording layer 12 having been provided, and opposite to on both sides of non-magnetic metal layer 11. As a material of non-magnetic metal layer 11, the metal only consisting of any of Cu, Au, Ag, or Ru or an element or the alloy containing at least one of the elements of these is used.

0042Like magneto-resistive effect element 1 by the modification of a 2nd embodiment shown in Drawing 13, it is good in a 1st embodiment shown in Drawing 5 also as composition which provided magnetic field adjustment layer 10 in the side that spacer layer 18 of magnetic rotation layer 20 was provided, and opposite to on both sides of non-magnetic layer 11A. As non-magnetic layer 11A in this modification, the metal or the tunnel barrier layer which does not make a spin polarization electron penetrate may be sufficient. However, the non-magnetic layer which penetrates a spin polarization electron as this non-magnetic layer 11A, For example, it is preferred to consist of the oxide or nitriding thing containing the element of either the metal only consisting of the element of either Cu, Au, Ag or Ru, the alloy containing at least one of these elements or Mg, aluminum, Ti or Hf. It is because the spin injection rate to a magnetization rotation layer increases by using such materials as non-magnetic layer 11A, so it becomes possible to cause rotation of an efficient magnetization rotation layer.

0043The stable writing which does not have incorrect writing using unidirectional current can be performed like [ this 2nd embodiment and its modification ] a 1st embodiment. Compared with a 1st embodiment, it becomes possible to reduce the influence of the leak magnetic field from magnetism reference layer 16, and can make more stable the information recorded on magnetic recording layer 12.

0044(A 3rd embodiment)<br />The magneto-resistive effect element of a 3rd embodiment is shown in Drawing 14. In the magneto-resistive effect element of a 1st embodiment shown in Drawing 5, magneto-resistive effect element 1 of this 3rd embodiment has composition using antiferromagnetism joint film 20A as magnetic rotation layer 20. This antiferromagnetism joint film 20A has the lamination structure where ferromagnetic layer 20a, non-magnetic layer 20b, and ferromagnetic layer 20c were laminated in this order, on spacer layer 18, and ferromagnetic layer 20a and ferromagnetic layer 20c are carrying out antiferromagnetism combination via non-magnetic layer 20b.

0045In the magneto-resistive effect element by the 1st thru/or a 2nd embodiment, since the magnetic film (field inner-magnet-ized film) which has field inner-magnet-ization is used as magnetic rotation layer 20, magnetic domain structure with a complicated vortex magnetic domain structure etc. may arise. If there is magnetic domain structure, in order that the rotation at the time of spin pouring from magnetism reference layer 16 being performed may be checked mutually and rotation efficiency may fall, it is desirable for magnetic domain structure not to arise in magnetic rotation layer 20. A field inner-magnet-ized film has the character which is formed into a single magnetic domain and magnetic domain structure does not produce by generally making element size small. In order to carry out by not producing magnetic domain structure in the magnetic rotation layer which is a field inner-magnet-ized film, an antiferromagnetism joint film may be used as magnetic rotation layer 20A like a 3rd embodiment.

0046Therefore, magneto-resistive effect element 1 of a 3rd embodiment can prevent the rotation efficiency of magnetic rotation layer 20A from falling. The stable writing which does not have incorrect writing using unidirectional current can be performed like [ magneto-resistive effect element 1 of a 3rd embodiment ] a 1st embodiment.

0047In a 3rd embodiment, it is also possible to make the hand of cut of the microwave magnetic field impressed from magnetic rotation layer 20A to magnetic recording layer 12 into the case of the magnetic rotation layer formed by the single film and a contrary by distinguishing between the film thickness of ferromagnetic layers 20a and 20c of antiferromagnetism joint film 20A.

0048(A 4th embodiment)<br />The magneto-resistive effect element by a 4th embodiment is shown in Drawing 15. In the magneto-resistive effect element of a 1st embodiment shown in Drawing 5, as magnetic recording layer 12, magneto-resistive effect element 1 of a 4th embodiment laminates field inner-magnet-ized film 12b on perpendicular magnetization film 12a, and has composition using laminated type magnetic recording layer 12A.

0049In the 1st thru/or the magneto-resistive effect element of a 3rd embodiment, the resonant frequency of a magnetic recording layer serves as a parameter important for resonance magnetic field writing. The resonant frequency of a magnetic recording layer is dependent on anisotropy energy so that it may be expressed with the formula of Kittel, i.e., (5) types. Therefore, resonant frequency can be freely changed by using laminated type magnetic recording layer 12A as a magnetic recording layer like a 4th embodiment. Although field inner-magnet-ized film 12b does not have perpendicular magnetic anisotropy at this time, the magnetization direction is perpendicularly suitable by carrying out exchange combination with perpendicular magnetization film 12a, as shown in Drawing 15. Generally, if a field inner-magnet-ized film is laminated on a perpendicular magnetization film, the whole anisotropy energy will fall. For this reason, the resonant frequency of magnetic recording layer 12A of a 4th embodiment can turn into desired frequency. L1 which contains at least one element in Fe, Co, and nickel, and at least one element in Pt and Pd as perpendicular magnetization film 12a_０It is preferred to use the magnetic body which has a hexagonal type crystal structure which uses a magnetic body with a model crystal structure, or contains at least one element in Fe, Co, and nickel and at least one element in Cr, Ta, Pt, and Pd. Fe, Co, nickel, and the alloy that contains at least one element among Mn can be used as field inner-magnet-ized film 12b in these cases.

0050It is Cu between perpendicular magnetization film 12a and perpendicular magnetization film 12d like magneto-resistive effect element 1 of the modification shown in Drawing 16, Even if it uses perpendicular type SAF joint film 12B which provided spacer layer 12c containing the element of either Au, Ag or Ru, and carried out antiferromagnetism combination, it is possible to produce similarly magnetic recording layer 12B to which resonant frequency was changed compared with the 1st thru/or a 3rd embodiment.

0051The stable writing which does not have incorrect writing using unidirectional current can be performed like [ this 4th embodiment and its modification ] a 1st embodiment.

0052Even if it combines the 2nd thru/or a 4th embodiment suitably, the stable writing which does not have incorrect writing using unidirectional current can be performed like a 1st embodiment.

0053(A 5th embodiment)<br />Next, the magnetic random access memory (MRAM) by a 5th embodiment is shown in Drawing 17.<br />MRAM of this embodiment is provided with memory cell array 100 which has memory cell MC arranged in the shape of a matrix. And each memory cell MC is provided with either or magneto-resistive effect element 1 combined, respectively of the 1st thru/or a 4th embodiment, and its modification.

0054A plurality of bit line pair BL(s) and /BL are arranged at memory cell array 100 so that each may extend in the direction of a sequence (column). A plurality of word lines WL are arranged at memory cell array 100 so that each may extend in the direction of a line (low).

0055Memory cell MC is arranged at the crossing portion of bit line BL and word line WL. Each memory cell MC has magneto-resistive effect element 1 and selection transistor 40. The end of magneto-resistive effect element 1 is connected to bit line BL. The other end of magneto-resistive effect element 1 is connected to the Dorain terminal of selection transistor 40. The gate terminal of selection transistor 40 is connected to word line WL. The sauce terminal of selection transistor 40 is connected to a bit line/BL.

0056Low decoder 50 is connected to word line WL. A write-in circuit and readout circuitry 60 are connected to bit line pair BL and /BL. Column decoder 70 is connected to a write-in circuit and readout circuitry 60. Each memory cell MC is chosen by low decoder 50 and column decoder 70.

0057The data writing to memory cell MC is performed as follows. First, in order to choose memory cell MC which performs data writing, word line WL connected to this memory cell MC is activated. Thereby, selection transistor 40 turns on.

0058Here, the write-in current of only one way should just be supplied to magneto-resistive effect element 1. When writing in magneto-resistive effect element 1 from the left on a drawing on the right and specifically supplying current Iw, a write-in circuit and the write-in circuit in readout circuitry 60 impress positive potential to bit line BL, and impress earth potentials to a bit line/BL. Thus, data "0" or data "1" can be written in memory cell MC.

0059Data read-out from memory cell MC is performed as follows. First, memory cell MC is chosen. The readout circuitry in a write-in circuit and readout circuitry 60 supplies read-out current Ir which flows into the left from the right, for example on a drawing to magneto-resistive effect element 1. And the above-mentioned readout circuitry detects the resistance of magneto-resistive effect element 1 based on this read-out current Ir. Thus, the information memorized by magneto-resistive effect element 1 can be read. In MRAM of this 5th embodiment, since it becomes unnecessary to carry the peripheral circuit for writing bidirectionally and sending current, it becomes easy to realize mass MRAM with the high cell share.

0060(A 6th embodiment)<br />MRAM by a 6th embodiment is shown in Drawing 18. MRAM of a 6th embodiment has the crosspoint type architecture. That is, MRAM of a 6th embodiment has composition provided with memory cell MC containing magneto-resistive effect element 1 of either the 1st thru/or a 4th embodiment, and diode 80 between bit line BL and word line WL. PN diode and a Schottky diode can be used as diode 80. The rectifier which has the rectification function to send current may be used only for one way instead of diode 80. In Drawing 18, although diode 80 was formed in the bit line side, it may provide in the word line WL side.

0061Since current can be sent only through one way in a 6th embodiment, it is in writing, The 1st and 2nd write-in current explained by a 1st embodiment is used, and it is as read-out current, It is preferred to use the current value which is a current value in which magnetic rotation layer 20 generates the microwave magnetic field which has the rotation frequency [ resonant frequency / of magnetic recording layer 12 ] shifted, and the magnetization direction of magnetic recording layer 12 does not reverse by spin pouring.

0062In this case, it is possible to choose the memory cell which performs writing and read-out with the combination of a low decoder and a column decoder. In MRAM of this 6th embodiment, since it becomes unnecessary to carry a selection transistor in each memory cell, it becomes possible to realize mass MRAM with the high cell share.

0063MRAM of a 6th embodiment has composition which equipped a lower layer and the upper layer with the crosspoint type architecture, respectively as shown in Drawing 18, If it arranges so that wiring BL corresponding to the same position in the crosspoint type architecture of a lower layer and the upper layer, for example, a bit line, may be shared, it is possible to form laminated type MRAM. If circuit composition shown in Drawing 18 is made into a unit hierarchy, it is possible to laminate N times and to form on a principle, the super-bulk memory to which capacity per unit area was increased N times.

0064Although some embodiments of the present invention were described, these embodiments are shown as an example and limiting the scope of an invention does not have intention of them. These embodiments can be carried out with other various forms, are the ranges which do not deviate from the gist of an invention, and various abbreviations and replacement are performed and they can make a change. When these embodiment and its modification are included in the range and gist of an invention, they are similarly included in the invention indicated to the claim, and its equivalent range.