Magnetic laminated film, magnetic memory element, and magnetic memory

Abstract

To provide a magnetic laminated film suitable for use in a spin-orbit torque writing type MRAM (SOT-MRAM).SOLUTION: A magnetic laminated film for a magnetic memory element includes a channel layer 10 that generates a spin current for magnetic reversal, and a first ferromagnetic layer 20 adjacent to the channel layer 10 and containing a ferromagnetic layer with reversible magnetization, and the channel layer 10 is made of Ru1-xCux (0.10≤x≤0.90), and the thickness of the channel layer 10 is in the range of 2 nm to 30 nm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic laminated film, a magnetic memory element, and a magnetic memory. [Background technology]

[0002] As a new non-volatile memory device using spintronics technology, the development of three-terminal magnetic random access memory (MRAM), which is expected to operate at high speed, is progressing. In three-terminal MRAM, attention has been focused on spin-orbit torque-write MRAM (SOT-MRAM), which realizes magnetization reversal by inducing a magnetic torque called spin-orbit torque to write information (magnetization reversal of the magnetic layer) [Non-Patent Document 1]. To achieve this, the write channel layer (spin current generation layer) is required to be capable of generating a large spin current and also to have a small electrical resistance.

[0003] Patent Document 1 discloses a magnetic laminated film having a structure in which a heavy metal layer 10 containing a 5d transition metal, such as tungsten (W) or tantalum (Ta), and a first ferromagnetic layer 20 are stacked adjacent to each other, and proposes a magnetic laminated film for a magnetic memory element in which the direction in which the spin-orbit torque acts is determined by the combination of materials used for the heavy metal layer 10, the first ferromagnetic layer 20, and the barrier layer 30, and thereby the direction of the current when writing "1" and "0" is determined. Patent Document 2 proposes a magnetic memory device that includes a spin injection magnetization reversal process in which a reversal spin current is injected into the ferromagnetic metal thin film 2 through a reversal lead wire 3 in order to reverse the magnetization direction of the ferromagnetic metal thin film 2, and an auxiliary spin current injection process in which an auxiliary spin current is injected into the ferromagnetic metal thin film 2 through an auxiliary lead wire 4 in order to assist in reversing the magnetization direction of the ferromagnetic metal thin film 2, thereby reversing the magnetization direction of the ferromagnetic metal thin film 2 at high speed with a small current density.

[0004] SOT-MRAM has a thin non-magnetic layer (channel) that acts as a spin current generating wiring to generate spin orbit torque. When a magnetic tunnel junction (MTJ) that will be a memory cell is placed adjacent to this spin current generating wiring and a current is passed along the spin current generating wiring, a flow of electron spins, called a "spin current," is generated in a direction perpendicular to the current. This spin current applies a sufficiently large torque to the magnetic layer on one side of the adjacent MTJ, causing magnetization reversal. This structure allows different current paths to be used for reading and writing recorded information in the MTJ, which allows for a wide operating margin, enabling high-speed operation and greatly improving the durability of the element. However, a high spin current generation efficiency is required for operation. The spin Hall angle (= generated spin current / passed current) is used as an index of this efficiency. In addition, this layer must have low resistance because it also serves as electrical wiring between elements. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2017 / 208576 publication [Patent Document 2] JP 2020-194927 A [Patent Document 3] WO2020 / 166722 publication [Non-patent literature]

[0006] [Non-Patent Document 1] V. Krizakova, M. Perumkunnil, S. Couet, P. Gambardella, K. Garello, J. Magn. Magn. Mater., Vol. 562, p. 169692 (2022). [Non-Patent Document 2] Y. Niimi, M. Morota, D. H. Wei, C. Deranlot, M. Basletic, A. Hamzic, A. Fert, and Y. Otani, Phys. Rev. Lett., Vol. 106, p. 126601 (2011). [Non-Patent Document 3] Z. Wen, J. Kim, H. Sukegawa, M. Hayashi, and S. Mitani, AIP Adv., Vol. 6, p. 056307 (2016) [Non-Patent Document 4] Angew. Chem. Int. Ed., Vol. 58, pp. 2230-2235 (2019). [Non-Patent Document 5] H. Masuda, R. Modak, T. Seki, K. Uchida, Y.-C. Lau, Y. Sakuraba, R. Iguchi, and K. Takanashi, Commun Mater., Vol. 1, p. 75 (2020). [Non-Patent Document 6] C.O. Avci, K. Garello, A. Ghosh, M. Gabureac, S.F. Alvarado, and P. Gambardella, Nature Phys., Vol. 11, pp. 570-576 (2015). [Non-Patent Document 7] C. O. Avci, K. Garello, M. Gabureac, A. Ghosh, A. Fuhrer, S. F. Alvarado, P. Gambardella, Phys. Rev. B Vol. 90, p. 224427 (2014). [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] Both Ru and Cu are low-resistance metals, but their spin-current conversion efficiency is very small (spin Hall angle: Cu ~ 0 [Non-Patent Document 2], Ru ~ 0.56% [Non-Patent Document 3]), and they could not be used as spin-current generating layers. Ru-Cu is a combination that does not form an alloy in bulk, and the solid solubility range of each is very narrow, so alloying was thought to be difficult. Very recently, it has been reported that Ru-Cu can be alloyed in the case of nanometer-scale particles [Non-Patent Document 4]. However, it was unknown whether Ru-Cu could be stably obtained as a thin film larger than nanometer-scale particles, and even if a Ru-Cu alloy could be obtained as a thin film, its spin Hall effect was unknown.

[0008] The present invention is intended to solve these problems, and has an object to provide a magnetic multilayer film suitable for use in spin-orbit torque writing MRAM (SOT-MRAM). Another object of the present invention is to provide a magnetic memory element and a magnetic memory using the above magnetic laminated film. [Means for solving the problem]

[0009] The inventors conducted repeated experiments to explore the possibility of spin current generation at each interface of Ru / Cu by forming a laminated film of atomic thickness. However, unexpectedly, contrary to initial expectations, it was found that Ru-Cu could be obtained as a homogeneous solid solution (nano-artificial alloy film). A factor that is thought to have contributed to the realization of this nano-alloy generation is the promotion of forced solid solution formation by the high-energy sputtering process. In addition, Ru and Cu are a combination that allows single crystal growth, and the lattice matching is relatively good, which is also thought to be a factor in the formation. It was found that alloying can obtain a spin Hall angle (3.5%) that is orders of magnitude larger than pure Cu and pure Ru, and it was found to be a promising material for spin currents for spintronics elements, which led to the invention. It has been reported that the efficiency of spin current generation is improved by alloying beyond the solid solubility range in the Cu-Ir system [Non-Patent Document 5]. On the other hand, the present invention is a completely non-solid-solution system, unlike Cu-Ir, which has a solid solubility range. In addition, Ir itself exhibits a large spin Hall effect, which is different from the present invention, in that the effect is small as a pure metal.

[0010] [1] The magnetic laminated film of the present invention is a magnetic laminated film for a magnetic memory element, as shown in FIG. The magnetic field generating device includes a channel layer 10 for generating a spin current for magnetic reversal, and a first ferromagnetic layer 20 adjacent to the channel layer 10 and including a ferromagnetic layer having a reversible magnetization, The channel layer 10 is Ru 1-x Cu x (0.10≦x≦0.90), and the film thickness of the channel layer 10 is in the range of 2 nm to 30 nm. [2] In the magnetic laminated film [1] of the present invention, the crystal structure of the channel layer is preferably a hexagonal close-packed (HCP) structure for a Ru-rich composition, a cubic close-packed (FCC) structure for a Cu-rich composition, and both the hexagonal close-packed and cubic close-packed structures are present between the Ru-rich and Cu-rich compositions. [3] In the magnetic laminated film [1] or [2] of the present invention, the channel layer 10 is preferably made of Ru 1-x Cu x It is preferable that (0.25≦x≦0.75). [4] In the magnetic laminated film [1] to [3] of the present invention, it is preferable to further include a conductive non-magnetic layer inserted between the channel layer 10 and the first ferromagnetic layer 20, and the thickness of the non-magnetic layer is in the range of 0.2 nm to 10 nm. [5] The magnetic laminated film [1] to [4] of the present invention preferably further includes a substrate 70 on which the channel layer 10 and the first ferromagnetic layer 20 are laminated.

[0011] [6] The magnetic memory element of the present invention is characterized by comprising, as shown in, for example, Figures 2 to 6, a magnetic laminated film according to any one of items [1] to [4], a barrier layer 30 adjacent to the first ferromagnetic layer 20 and made of an insulating material, a reference layer 40 adjacent to the barrier layer 30 and having at least one ferromagnetic layer whose magnetization direction is fixed, a cap layer 50 adjacent to the reference layer 40 and made of a conductive material, a first terminal T1 at one end of the channel layer 10 in the longitudinal direction through which a current can be introduced, a second terminal T2 at the other end of the channel layer 10 in the longitudinal direction through which a current can be introduced, and a third terminal T3 at the cap layer 50 through which a current can be introduced. [7] In the magnetic memory element [6] of the present invention, a fourth terminal T4 may be provided connected to the first ferromagnetic layer 20. [8] In the magnetic memory element [6] of the present invention, the first ferromagnetic layer 20 may have a magnetization that can be reversed in a direction perpendicular to the out-of-plane direction of the film surface. [9] In the magnetic memory element [6] of the present invention, the first ferromagnetic layer 20 may have a magnetization that is reversible in a direction perpendicular to a line segment connecting the first terminal T1 and the second terminal T2 within the film plane.

[10] In the magnetic memory element [6] of the present invention, the first ferromagnetic layer 20 may have a magnetization that can be reversed in a direction parallel to a line segment connecting the first terminal T1 and the second terminal T2 within the film plane.

[11] In the magnetic memory element [6] of the present invention, the first ferromagnetic layer 20 has a first magnetization region, and a second magnetization region and a third magnetization region arranged on either side of the first magnetization region, the magnetization of the second magnetization region and the magnetization of the third magnetization region are fixed in different directions from each other, The magnetization of the first magnetization region may be reversible and may be oriented in the same direction as either the magnetization of the second magnetization region or the magnetization of the third magnetization region.

[0012]

[12] A magnetic memory of the present invention comprises: a magnetic memory element according to any one of [6] to

[11] ; a write means for writing data into the magnetic memory element by passing a write current through the magnetic memory element; and reading means for reading data written in the magnetic memory element by passing a current through the barrier layer 30 to obtain a tunnel resistance. Effect of the Invention

[0013] According to the magnetic laminated film of the present invention, the thin film of alloyed Ru and Cu greatly improves the efficiency of spin current generation, making it suitable for use in a magnetic device structure that is the basic structure for spin-orbit torque writing MRAM (SOT-MRAM). The magnetic memory element and magnetic memory of the present invention use a magnetic laminated film in which the spin current generation efficiency is greatly improved by a thin film alloyed with Ru and Cu, so that a high-performance spin-orbit torque writing type MRAM (SOT-MRAM) can be provided. [Brief description of the drawings]

[0014] [Figure 1] 1 is a front view showing a structure of a magnetic laminated film according to an embodiment of the present invention; [Figure 2A] FIG. 2 is a perspective view of a magnetic memory element using the magnetic laminated film of FIG. [Figure 2B] FIG. 2B is a front view (XZ plane) of the magnetic memory element of FIG. 2A. [Figure 2C] FIG. 2B is a side view (YZ plane) of the magnetic memory element of FIG. 2A. [Figure 2D] FIG. 2B is a plan view (XY plane) of the magnetic memory element of FIG. 2A. [Diagram 3] 2A and 2B are diagrams showing the memory states of the magnetic memory element of FIG. 2A, where (A) is the magnetization state when "0" is stored, and (B) is the magnetization state when "1" is stored. [Figure 4] 2A and 2B are diagrams showing a method for writing information to the magnetic memory element of FIG. 2A, where (A) shows a method for writing "1" and (B) shows a method for writing "0." [Diagram 5](A) and (B) are diagrams showing a method of reading information from the magnetic memory element of Figure 2A, where (A) is a method of reading when a "0" is stored, and (B) is a method of reading when a "1" is stored. [Figure 6] 2B is a diagram showing an example of a circuit configuration of a memory cell circuit for one bit using the magnetic memory element of FIG. 2A. FIG. [Figure 7] 7 is a block diagram of a magnetic memory in which a plurality of memory cell circuits shown in FIG. 6 are arranged. [Figure 8A] FIG. 13 is a plan view (XY plane) of a magnetic memory element according to a modified example of the present invention. [Figure 8B] FIG. 13 is a plan view (XY plane) of a magnetic memory element according to a modified example of the present invention. [Figure 8C] FIG. 13 is a plan view (XY plane) of a magnetic memory element according to a modified example of the present invention. [Figure 8D] FIG. 13 is a plan view (XY plane) of a magnetic memory element according to a modified example of the present invention. [Figure 9] FIG. 2B is a diagram for explaining the film thickness of the magnetic memory element in FIG. 2A. [Figure 10] FIG. 13 is a front view (XZ plane) of a magnetic memory element according to a modified example of the present invention. [Figure 11] (a) is a cross-sectional schematic diagram of a stacked device having a Ru50Cu50 spin current generation layer according to one embodiment of the present invention, (b) shows the stacked state of the Ru50Cu50 thin film, and (c) shows the external magnetic field dependence of the USMR signal (current density 9 MA / cm2). [Figure 12] 1A is a cross-sectional STEM image of a Ru50Cu50 spin current generation layer according to an embodiment of the present invention, and FIG. 1B is an energy dispersive X-ray spectrometry (EDS) composition profile of Cu atoms and Ru atoms. [Figure 13](a) is a schematic diagram of the structure of a stacked device using a Ru50Cu50 spin current generating layer and a CoFeB magnetic layer, (b) is the in-plane magnetic field angle dependence of the harmonic Hall signal (fundamental component), (c) is the in-plane magnetic field direction dependence of the harmonic Hall signal (second harmonic component), and (d) is a plot of the A component against the magnetic field. The solid lines in (b) to (d) show the results of fitting to theoretical equations. [Figure 14] (a) is a schematic cross-sectional view of a stacked device using the Ru25Cu75 composition, (b) shows the stacked state of the Ru25Cu75 thin film, and (c) shows the EDS composition depth profile of the fabricated stacked device. [Figure 15] (a) is a schematic cross-sectional diagram of a stacked device using the Ru75Cu25 composition, (b) shows the stacked state of the Ru75Cu25 thin film, and (c) shows the EDS composition depth profile of the fabricated stacked device. [Figure 16] The current density dependence of the USMR saturation signal value for each RuCu composition is shown. (a) shows the Ru25Cu75 composition, (b) shows the Ru50Cu50 composition, and (c) shows the Ru75Cu25 composition. [Figure 17] (a) is a schematic cross-sectional view of a stacked device having a Ru50Cu50 spin current generation layer formed on a single crystal Ru underlayer, (b) shows the stacked state of the Ru50Cu50 thin film, (c) shows a cross-sectional STEM image near the Ru50Cu50 of the stacked device, and (d) shows the external magnetic field dependence of the USMR signal (current density 27 MA / cm2). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The best mode for carrying out the present invention will now be described in detail. FIG. 1 is a front view showing the structure of a magnetic multilayer film according to an embodiment of the present invention. The magnetic multilayer film has a structure in which a channel layer 10 and a first ferromagnetic layer 20 are laminated adjacent to each other. The channel layer 10 is located on the substrate 70 side, and the first ferromagnetic layer 20 is located on the protective layer 80 side. Here, "adjacent" includes not only a directly adjacent structure but also a structure arranged via other layers, spaces, etc. within a range that does not impair the functions described below. The same applies in the following description.

[0016] The channel layer 10 generates a spin current for magnetic reversal, and is composed of Ru 1-x Cu x (0.10 ≦ x ≦ 0.90, more preferably 0.25 ≦ x ≦ 0.75). The crystal structure of Ru 1-x Cu x is a hexagonal close-packed structure (HCP) in a Ru-rich composition and a face-centered cubic structure (FCC) in a Cu-rich composition. Both the hexagonal close-packed structure and the face-centered cubic structure exist between the Ru-rich composition and the Cu-rich composition. Here, the Ru-rich composition refers to the range of 0.10 ≦ x ≦ 0.40. The Cu-rich composition refers to the range of 0.60 ≦ x ≦ 0.90. The intermediate between the Ru-rich composition and the Cu-rich composition refers to the range of 0.40 < x < 0.60. When x is less than 0.10 (more than 0.90), it is physically difficult to realize because the number of stacked layers is at least 1 layer (9 layers) when the number of stacked layers is equivalent to 10 atomic layers. Also, even if a homogeneous alloy could be obtained when x is less than 0.10 and more than 0.90, the effect is lost because the concentration of one of the atoms is too thin. Preferably, the film thickness of the channel layer 10 is 2 nm to 30 nm, and more preferably 4 nm to 10 nm. When the film thickness is less than 2 nm, it is difficult to thin the film during fabrication and it is difficult to function as an electrical wiring. When the film thickness is more than 30 nm, the spin diffusion length of the elements constituting the film is approached and the spin current generation function weakens. The film thickness here refers to the thickness of the portion of the channel layer 10 adjacent to the first ferromagnetic layer 20. For example, in the magnetic memory element 100 shown in FIG. 2A, the film thickness refers to the thickness of the region of the channel layer 10 on which the first ferromagnetic layer 20 is formed. Also, the unidirectional spin Hall magnetoresistance (USMR) signal of the channel layer 10 is typically 10 MA / cm 2 At a current density of 0.5 to 1.5 mΩ.

[0017] The first ferromagnetic layer 20 is made of a ferromagnetic material and has a property that the direction of magnetization (direction from S to N) held therein is reversible. The reversible direction of magnetization in the first ferromagnetic layer 20 is indicated by an arrow in FIG. 1. In the embodiment shown in FIG. 1, the direction of magnetization is reversible between upward and downward in a direction perpendicular to the out-of-plane of the film surface. The thickness of the first ferromagnetic layer 20 is 0.5 nm to 10 nm, more preferably 0.8 to 5 nm, and can be used for both in-plane magnetization film and perpendicular magnetization film. The magnetic layer material can be CoFeB, Co-Fe, Ni-Fe, Ni, Ni-Cu, or Co, and the perpendicular film can be a (Co,Fe)-(Pt,Pd) alloy or the like.

[0018] The substrate 70 is a magnetic laminate film having a channel layer 10 and a first ferromagnetic layer 20 laminated in this order. 2 O 3 Sapphire (0001) substrates, silicon substrates, MgO substrates, etc. are used. The protective layer 80 is made of, for example, an MgO layer, and functions as an oxidation protection film. The protective layer 80 is formed by depositing an Mg layer on the first ferromagnetic layer 20 by, for example, sputtering. After being taken out into the air, the Mg layer is naturally oxidized and changes to MgO, becoming the protective layer 80. Note that the protective layer 80 is provided in Examples 1 to 4 described later in order to measure the function of the spin current generation layer of the magnetic laminated film, and is not provided when used in the magnetic memory element 100.

[0019] Fig. 2A shows the structure of a magnetic memory element 100 using a magnetic laminated film. A front view (XZ plane) of the magnetic memory element 100 is shown in Fig. 2B, a side view (YZ plane) is shown in Fig. 2C, and a plan view (XY plane) is shown in Fig. 2D.

[0020] 2A to 2C, the magnetic memory element 100 is configured by laminating a magnetic laminated film made of a channel layer 10 and a first ferromagnetic layer 20, a barrier layer (insulating layer) 30, a reference layer 40, and a cap layer 50 in this order, and further includes a first terminal T1, a second terminal T2, and a third terminal T3. The first terminal T1 is connected to one end of the magnetic laminated film, and the second terminal T2 is connected to the other end of the magnetic laminated film. In detail, the first terminal T1 and the second terminal T2 are connected to both ends of the channel layer 10 of the magnetic laminated film. The substrate is omitted from the drawings to facilitate understanding when illustrating the first terminal T1 and the second terminal T2. Similarly, the substrate is omitted from the drawings below. In the following description, an XYZ coordinate system is set in which the long axis (extension direction) of the magnetic laminated film is the X direction, the short axis direction is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction, and will be referred to as appropriate.

[0021] The barrier layer 30 is provided adjacent to the first ferromagnetic layer 20 of the magnetic laminated film. The barrier layer 30 is made of an insulating material, such as MgO, Al-O, Mg-Al-O, or Mg-Ga-O, and may be made of a laminated film of these materials.

[0022] The reference layer 40 includes at least one ferromagnetic layer. In this embodiment, the reference layer 40 has a structure in which a second ferromagnetic layer 41, a coupling layer 42, and a third ferromagnetic layer 43 are stacked in this order. The reference layer 40 may have one ferromagnetic layer or three or more ferromagnetic layers. The magnetization directions of the ferromagnetic layers constituting the reference layer 40 (more precisely, the second ferromagnetic layer 41 adjacent to the barrier layer 30) are substantially fixed. The magnetization of the second ferromagnetic layer 41 is substantially fixed upward, and the magnetization of the third ferromagnetic layer 43 is substantially fixed downward. The coupling layer 42 functions to couple the magnetization directions of the second ferromagnetic layer 41 and the third ferromagnetic layer 43 in antiparallel directions. In this case, the Ruderman Kittel Kasuya Yoshida (RKKY) interaction or the like can be used as the coupling mechanism. By coupling the two ferromagnetic layers in an antiparallel direction via the coupling layer 42, the total magnetic field applied to the first ferromagnetic layer 20 can be reduced, and the energies of the two memory states (up and down magnetization states) can be made symmetrical. In addition, the leakage magnetic field from the reference layer 40 can be reduced.

[0023] The first ferromagnetic layer 20, the barrier layer 30, and the second ferromagnetic layer 41 form a magnetic tunnel junction. The cap layer 50 is made of a conductive material. The cap layer 50 has a function of protecting the above-mentioned magnetic tunnel junction. When an in-plane magnetization film is used for each magnetic layer instead of the illustrated perpendicular magnetization film, an antiferromagnetic layer is introduced between the cap layer 50 and the reference layer 40 to control the magnetization arrangement. Ir-Mn, Pt-Mn, or the like having a thickness of 5 to 15 nm can be used as the antiferromagnetic layer. A third terminal T3 is connected to the cap layer 50.

[0024] As shown in FIG. 2B, the magnetic memory element 100 has three terminals. However, the magnetic memory element according to the present embodiment may have three or more terminals. For example, the first terminal T1 and the second terminal T2 may be connected to the channel layer 10, the third terminal T3 may be connected to the cap layer, and the fourth terminal (not shown) may be connected to the fourth ferromagnetic layer (not shown). In these structures, the fourth ferromagnetic layer is adjacent to the barrier layer 30 and is provided between the barrier layer 30 and the first ferromagnetic layer 20. The fourth ferromagnetic layer has a reversible magnetization, and its direction changes to reflect the direction of the magnetization of the first ferromagnetic layer 20. The fourth terminal may also be disposed on the first ferromagnetic layer 20. That is, the fourth terminal may be electrically connected directly or indirectly to the first ferromagnetic layer 20.

[0025] Next, the magnetization structure when the magnetic memory element 100 stores information "0" or "1" will be described with reference to FIG.

[0026] FIG. 3(A) is a front view showing a schematic magnetization structure of the magnetic memory element 100 when the information "0" is stored, and FIG. 3(B) is a front view showing a schematic magnetization structure when the information "1" is stored. When the magnetic memory element 100 stores "0", the magnetization of the first ferromagnetic layer 20 is directed upward. This makes the magnetization direction in the magnetic tunnel junction parallel. When the magnetic memory element 100 stores "1", the magnetization of the first ferromagnetic layer 20 is directed downward. This makes the magnetization direction in the magnetic tunnel junction antiparallel. The definition of the memory storage data and the magnetization state is arbitrary, and may be, for example, the opposite of the relationship shown in FIG. 3. The magnetic memory element 100 may be formed of an in-plane magnetization film as long as the parallel and antiparallel states can be realized.

[0027] Next, a method for writing information "0" and "1" to the magnetic memory element 100 will be described with reference to Fig. 4. Fig. 4(A) is a diagram for explaining the operation when writing "1", and Fig. 4(B) is a diagram for explaining the operation when writing "0".

[0028] Magnetization reversal due to spin-orbit torque is used when writing information to the magnetic memory element 100. For this reason, a write current flows in the in-plane direction of the channel layer 10 via the first terminal T1 and the second terminal T2.

[0029] In the magnetic memory element 100, the first ferromagnetic layer 20, which is responsible for storing information, has a magnetization direction that can be reversed in the perpendicular direction. In order to reverse the perpendicular magnetization direction by spin-orbit torque, a stationary magnetic field parallel to the current is required. As shown in FIG. 4, a magnetic field H X is applied.

[0030] When writing “1” to the magnetic memory element 100, the write current IW 1 is passed from the first terminal T1 through the channel layer 10 to the second terminal T2. On the other hand, when writing "0" to the magnetic memory element 100, a write current IW 0 is caused to flow from the second terminal T2 through the channel layer 10 to the first terminal T1.

[0031] This allows the memory to go back and forth between a state in which "0" defined in Fig. 3(A) is stored and a state in which "1" defined in Fig. 3(B) is stored. The relationship between the direction of the write current, the direction of the in-plane steady magnetic field, and the direction of magnetization reversal can vary depending on the combination of materials used for the channel layer 10, the first ferromagnetic layer 20, and the barrier layer 30. More specifically, the direction in which the spin-orbit torque acts is determined by the combination of materials used for the channel layer 10, the first ferromagnetic layer 20, and the barrier layer 30, which determines the direction of the current when writing "1" and when writing "0".

[0032] The mechanism by which the spin-orbit torque is generated is thought to be the spin Hall effect, the Rashba effect, etc. However, in the present invention, the principle may be any, as long as a torque acts on the magnetization of the first ferromagnetic layer 20 via the spin-orbit interaction when a current is introduced into the magnetic laminated film, and this torque induces reversal by rotating the magnetization direction.

[0033] The required magnitude (density) of the write current and the pulse width are determined by the combination of materials used for the channel layer 10, the first ferromagnetic layer 20, and the barrier layer 30. The magnitude of the write current density is typically 0.2 to 2×10 12 A / m 2 In this case, assuming that a current flows through the channel layer 10, the width of the channel layer 10 in the Y direction is 50 nm, and the film thickness in the Z direction is 6 nm, the magnitude of the write current is 60 to 600 μA. The pulse width of the write current is typically 0.2 to 5 ns.

[0034] Next, a method for reading information "0" and "1" from the magnetic memory element 100 will be described with reference to FIG. When reading information from the magnetic memory element 100, the tunnel magnetoresistance effect is used. For this purpose, a read current is passed through the magnetic tunnel junction consisting of the first ferromagnetic layer 20, the barrier layer 30, and the reference layer 40, and reading is performed by utilizing the difference in tunnel resistance of the magnetic tunnel junction when "0" is stored and when "1" is stored. During reading, as shown in FIGS. 5(A) and (B), a read current I R is applied from the third terminal T3 to the first terminal T1 and the second terminal T2. At this time, in the state in which "0" is stored as shown in Fig. 5(A), the magnetization direction of the first ferromagnetic layer 20 and the magnetization direction of the second ferromagnetic layer 41 are parallel, so that the resistance is low and the current flowing due to the reference voltage is relatively large.

[0035] On the other hand, in the state where "1" is stored as shown in FIG. 5(B), the magnetization direction of the first ferromagnetic layer 20 and the magnetization direction of the second ferromagnetic layer 41 are antiparallel, so the resistance is high and the current flowing due to the reference voltage is relatively small. In other words, in the state where "0" is stored as shown in FIG. 5(A), the magnetization direction of the first ferromagnetic layer 20 and the magnetization direction of the second ferromagnetic layer 41 are parallel, so the resistance is low and the voltage required to flow the reference current is relatively small. On the other hand, in the state where "1" is stored as shown in FIG. 5(B), the magnetization direction of the first ferromagnetic layer 20 and the magnetization direction of the second ferromagnetic layer 41 are antiparallel, so the resistance is high and the voltage required to flow the reference current is relatively large.

[0036] In addition, when the magnetic memory element 100 has a structure having a fourth terminal (a fourth ferromagnetic layer provided between the barrier layer 30 and the first ferromagnetic layer 20, or a terminal provided on the first ferromagnetic layer 20), the read current can be passed between the third terminal T3 and the fourth terminal. The operation of passing the write current is the same as the above-mentioned operation.

[0037] (Memory cell circuit) Next, a configuration example of a memory cell circuit that uses the magnetic memory element 100 having the above configuration as a storage element will be described with reference to FIG. 6 shows the configuration of a one-bit magnetic memory cell circuit 200. The magnetic memory cell circuit 200 includes a magnetic memory element 100 constituting a one-bit memory cell, a pair of write bit lines WBL1 and WBL2, a word line WL, a read bit line RBL, a first transistor Tr1, and a second transistor Tr2.

[0038] The third terminal T3 of the magnetic memory element 100 is connected to the read bit line RBL. The first terminal T1 is connected to the drain of the first transistor Tr1, and the second terminal T2 is connected to the drain of the second transistor Tr2. The gate electrodes of the first transistor Tr1 and the second transistor Tr2 are connected to the word line WL. The source of the first transistor Tr1 is connected to the first write bit line WBL1, and the source of the second transistor Tr2 is connected to the second write bit line WBL2.

[0039] When writing information to the magnetic memory element 100, first, in order to select the magnetic memory element 100, an active level signal that turns on the transistors Tr1 and Tr2 is applied to the word line WL. Here, it is assumed that the transistors Tr1 and Tr2 are configured from N-channel MOS (Metal Oxide Semiconductor) transistors. In this case, the voltage of the word line WL is set to a high level. This causes the first transistor Tr1 and the second transistor Tr2 to be in an on state. Meanwhile, depending on the data to be written, the voltage of one of the first write bit line WBL1 and the second write bit line WBL2 is set to a high level, and the voltage of the other is set to a low level.

[0040] Specifically, when writing data “1”, the voltage of the first write bit line WBL1 is set to a high level, and the voltage of the second write bit line WBL2 is set to a low level. As a result, as shown in FIG. 4A, a write current IW flows in the forward direction to the channel layer 10. 1 flows, and data “1” is written in the magnetic memory element 100.

[0041] On the other hand, when writing data "0", the voltage of the first write bit line WBL1 is set to a low level, and the voltage of the second write bit line WBL2 is set to a high level. As a result, as shown in FIG. 4B, a write current IW flows in the channel layer 10 in the reverse direction. 0 flows, and data “0” is written in the magnetic memory element 100. In this manner, bit data is written to the magnetic memory element 100.

[0042] On the other hand, when reading information stored in the magnetic memory element 100, the word line WL is set to an active level, and the first transistor Tr1 and the second transistor Tr2 are turned on. The voltage of the read bit line RBL is set to a high level. A current flows from the read bit line RBL set to a high level voltage through the third terminal T3, the cap layer 50, the reference layer 40, the barrier layer 30, the first ferromagnetic layer 20, the channel layer 10, the first terminal T1, the second terminal T2, the first transistor Tr1, the second transistor Tr2, the first write bit line WBL1, and the second write bit line WBL2. By measuring the magnitude of this current, the magnitude of the resistance of the magnetic tunnel junction, i.e., the stored data, can be obtained.

[0043] The configuration and circuit operation of the magnetic memory cell circuit 200 are merely examples and may be modified as appropriate. For example, the third terminal T3 may be connected to the ground line GND instead of the read bit line RBL, and during reading, the voltages of both the first write bit line WBL1 and the second write bit line WBL2 may be set to a high level, or one of the voltages may be set to a high level and the other may be set to open, so that a current flows from the channel layer 10 to the cap layer 50.

[0044] Next, the configuration of a magnetic memory 300 including a plurality of magnetic memory cell circuits 200 will be described with reference to FIG. As shown in FIG. 7, the magnetic memory 300 includes a magnetic memory cell array 210, an X driver 120, a Y driver 130, and a controller 140.

[0045] The magnetic memory cell array 210 has magnetic memory cell circuits 200 arranged in an array of N rows and M columns. The magnetic memory cell circuits 200 in each column are connected to the first write bit line WBL1, the second write bit line WBL2, and the read bit line RBL in the corresponding column. In addition, the magnetic memory cell circuits 200 in each row are connected to the word line WL in the corresponding row.

[0046] The X driver 120 is connected to a plurality of word lines WL, receives a row address, decodes the row address, and drives the voltage of the word line WL of the row to be accessed to an active level (high level when the first and second transistors T11 and Tr2 are N-channel MOS transistors).

[0047] The Y driver 130 functions as a write means for writing data to the magnetic memory element 100 and as a read means for reading data from the magnetic memory element 100. The Y driver 130 is connected to a plurality of first write bit lines WBL1 and second write bit lines WBL2. The Y driver 130 receives a column address, decodes the column address, and sets the first write bit line BL1 and the second write bit line BL2 connected to the magnetic memory cell circuit 200 to be accessed to a desired data write state or read state.

[0048] That is, when writing data "1", the Y driver 130 sets the voltage of the first write bit line WBL1 connected to the magnetic memory cell circuit 200 to be written to at a High level and sets the voltage of the second write bit line WBL2 at a Low level. When writing data "0", the Y driver 130 sets the voltage of the first write bit line WBL1 at a Low level and sets the voltage of the second write bit line WBL2 at a High level.

[0049] Furthermore, when reading information stored in the magnetic memory cell circuits 200, the Y driver 130 sets the voltage of the read bit line RBL to a high level and connects the first write bit line WBL1 and the second write bit line WBL2 to ground. A sense amplifier (not shown) compares the current flowing through the read bit line RBL with a reference value to determine the resistance state of the magnetic memory cell circuits 200 in each column, thereby reading the stored data.

[0050] The controller 140 controls the X driver 120 and the Y driver 130 in response to data writing or data reading.

[0051] (Materials and sizes of magnetic laminated films and magnetic memory elements) Next, materials that can be used for the magnetic laminated film and the magnetic memory element 100 will be described.

[0052] The channel layer 10 generates a spin current for magnetic reversal and is made of at least Ru 1-x Cu x (0.10≦x≦0.90, more preferably 0.25≦x≦0.75). The crystal structure of the channel layer 10 is usually a hexagonal close-packed structure (HCP) for a Ru-rich composition, a cubic close-packed structure (FCC) for a Cu-rich composition, and both the hexagonal close-packed structure and the cubic close-packed structure exist between the Ru-rich composition and the Cu-rich composition. The USMR voltage signal of the channel layer 10 is, for example, 10 MA / cm within the above-mentioned Ru-Cu composition range. 2 This is a large value of about 0.5 to 1.5 mΩ at a current density of 100 kΩ.

[0053] The first ferromagnetic layer 20 contains at least Fe, Co, and Ni, and has spontaneous magnetization. In order to obtain desired magnetic properties and crystal structure, it may contain B, C, N, O, Al, Si, P, S, Ti, V, Cr, Cu, Zn, Ga, Ge, etc. Specific examples include Fe-Co alloys and Fe-Co-B alloys. The first ferromagnetic layer 20 may be a laminated film made of multiple ferromagnetic layers. For example, a laminated film of an Fe-Co alloy and an Fe-Co-B alloy is exemplified. The first ferromagnetic layer 20 may be a laminated film in which at least two ferromagnetic layers and at least one nonmagnetic layer are laminated. For example, a laminated film in which Co and Pt are alternately laminated with a thickness of sub-nanometer is exemplified.

[0054] The barrier layer 30 is made of an insulating material, such as Mg-O, Mg-Al-O, Al-O, or Mg-Ga-O. The materials that can be used for the second ferromagnetic layer 41 and the third ferromagnetic layer 43 constituting the reference layer 40 are the same as those of the first ferromagnetic layer 20. However, the second ferromagnetic layer 41 and the third ferromagnetic layer 43 need to be magnetically harder than the first ferromagnetic layer 20. The coupling layer 42 is preferably a conductive material that can magnetically couple the second ferromagnetic layer 41 and the third ferromagnetic layer 43. Specifically, Ru is exemplified. The film configuration of the reference layer 40 is exemplified by Fe-Co-B alloy / Ta / [Co / Pt] laminated film / Ru / [Co / Pt] laminated film, in that order from the barrier layer 30 side.

[0055] The cap layer 50 is made of a conductive material. Examples of such materials include Ta, Ru, W, and Pt. The cap layer 50 may also be a laminated film in which a plurality of conductive materials are laminated. Specifically, examples of such materials include Ta / Ru / Ta.

[0056] Next, the size and film thickness of the magnetic memory element 100 will be described with reference to FIG. 2A. The channel layer 10 has a shape extending in the X direction. When the channel layer 10 is formed in a rectangular shape in the XY plane, the typical size is as follows: the width in the Y direction is 20 to 150 nm; the length in the X direction is 50 to 800 nm. The channel layer 10 may have a shape other than a rectangle.

[0057] As shown in FIG. 2A, the first ferromagnetic layer 20, the barrier layer 30, the reference layer 40, and the cap layer 50 are formed in the same shape. However, they do not have to be the same shape. For example, only the first ferromagnetic layer 20 may be formed in the same shape as the channel layer 10. Furthermore, the shape is arbitrary. FIG. 2A shows an example in which the first ferromagnetic layer 20, the barrier layer 30, the reference layer 40, and the cap layer 50 are formed in a square shape, but they may be formed in a circular shape (FIG. 8A), a rectangular shape (FIG. 8B), or an elliptical shape (FIG. 8C). In this case, the length of one side (or the diameter, the short axis) is 20 to 150 nm. FIG. 2A shows an example in which the length in the Y direction of the first ferromagnetic layer 20, the barrier layer 30, the reference layer 40, and the cap layer 50 is the same as the length in the Y direction of the channel layer 10, but as shown in FIG. 8D, they may be different.

[0058] Next, the film thickness of each layer will be described with reference to FIG. The thickness t of the channel layer 10 10 The thickness t of the channel layer 10 is preferably 5 nm or more and 30 nm or less. 10 If the thickness t is less than 5 nm, it is not possible to ensure a sufficient process margin in the manufacturing process described below. 10 By setting the thickness t of the channel layer 10 to 5 nm or more, a sufficient process margin can be ensured. 10 If the thickness t of the channel layer 10 exceeds 30 nm, the write current becomes large. 10 refers to the film thickness of the portion adjacent to the first ferromagnetic layer 20. In other words, it means the thickness of the region of the channel layer 10 on which the first ferromagnetic layer 20 is formed.

[0059] The thickness t of the first ferromagnetic layer 20 20 is typically 0.5 nm or more and 10 nm or less. The thickness t of the barrier layer 30 30 is typically 0.8 nm or more and 3 nm or less. The total thickness t of the reference layer 40 40 is 2 nm or more and 15 nm or less. The thickness t of the cap layer 50 50is 1 nm or more and 50 nm or less.

[0060] (Example) Next, the results of experiments carried out by the inventors regarding the magnetic laminated film and the magnetic memory element 100 will be shown. EXAMPLES

[0061] Al with surface cleaning by heat treatment 2 O 3 A sapphire (0001) substrate (2 cm square) was placed in a vacuum chamber. The ultimate vacuum of the vacuum chamber was 10 -7 It is in the Pa range. A 2-inch magnetron sputter gun was used to alternately deposit Ru and Cu on the substrate, with a thickness of 0.2 nm, which corresponds to the thickness of one atomic plane. 50 Cu 50 A thin film was obtained (Figure 11(b)). The number of repeated laminations was 25. 50 Cu 50 The layer was fabricated to a thickness of approximately 10 nm. The substrate temperature during film formation was room temperature, and Ar pressure of 0.1 Pa was used as the process gas. The Ru layer was formed in direct current (DC) mode with an input power of 40 W, and the Cu layer was formed in radio frequency (RF) mode with an input power of 30 W.

[0062] Then, post-heat treatment was performed in a vacuum chamber at 300°C for 15 minutes. 80 Fe 20 A layer of NiFe was sputtered at a DC power of 20 W, and finally a protective layer of Mg was sputtered at an RF power of 30 W. After the Mg layer was taken out into the air, it was naturally oxidized and turned into MgO, resulting in the layered structure shown in Figure 11(a). 50 Cu 50 The layer is a spin current generating layer 10 serving as a channel layer, a NiFe layer is a magnetic layer 20 serving as a first ferromagnetic layer for detecting the spin current, and a MgO layer is a protective layer 80 functioning as an oxidation protective film.

[0063] Next, this laminated film was patterned to a width of 10 μm and a length of 25 μm using photolithography and argon ion milling, and a gold electrode approximately 100 nm thick was formed on the outside of it. The generation of spin current by the USMR method was confirmed at room temperature [Non-Patent Document 6]. Specifically, an AC sine wave current (227 Hz) was applied in the longitudinal direction (x direction) within the plane of the laminated film. The second harmonic component of the electrical resistance in the longitudinal direction was the USMR signal (R xx 2ω ) Figure 11(c) shows the current density Jc=9MA / cm 2 When using the external magnetic field (H y ) dependence. The final USMR signal value is the saturation value minus the effect of heat generation, which is determined by a separate measurement. In this sample, the effect of heat generation was found to be negligible (approximately 0.015 mΩ), and the USMR signal was estimated to be 1 mΩ. This value is the same as that of Ru under equivalent measurement conditions. 50 Cu 50 The measurement result at the same current density for the sample in which the Ru phase was replaced with a single-phase Ru film (10 nm) was ~0.007 mΩ, which is an order of magnitude larger than the ~0.002 mΩ for the Cu single-phase film (10 nm) sample. 50 Cu 50 It is clear that using a thin film as a spin current generation layer can achieve high spin current generation efficiency.

[0064] The Ru 50 Cu 50 To confirm the nanostructure of the thin film, a high-resolution high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) image of the sample cross section was obtained (Fig. 12(a)). As can be seen in Fig. 12(a), Ru 50 Cu 50The layer was obtained as a nearly homogeneous polycrystalline structure. It was also found that the crystal structure was a mixture of face-centered cubic (FCC) and hexagonal close-packed (HCP) structures. Figure 12(b) shows the results of local composition analysis by energy dispersive X-ray spectroscopy (EDS) obtained in an area of ​​the same size as the image in Figure 12(a). It can be seen that the composition of Ru and Cu is nearly homogeneous in the nanometer range, and the composition is also nearly 1:1 as designed. Although Ru and Cu are a combination of elements that do not normally form an alloy, it can be seen that the method of this embodiment forms a homogeneous alloy with a close-packed structure. It can be said that this alloying has improved the efficiency of spin current generation. EXAMPLES

[0065] The magnetic layer is made of 2 nm thick Co. 20 Fe 60 B 20 A laminate structure identical to that of the sample used in Example 1 was fabricated, except for the use of a (CoFeB) layer. A schematic diagram of this laminate structure is shown in FIG. 13(a). The CoFeB layer was deposited using a 3-inch magnetron sputtering gun under conditions of an Ar gas pressure of 0.07 Pa and DC 15 W. As in Example 1, electrodes were formed by patterning to a width of 10 μm and a length of 25 μm. Thereafter, the spin Hall angle was calculated by the harmonic Hall method [Non-Patent Document 7], which is a method different from that in Example 1. As in Example 1, an alternating current was applied in the longitudinal direction, and the Hall resistance R H The basic component R H ω and the second harmonic component R H ω We measured the in-plane magnetic field angle dependence of and estimated the spin Hall angle by fitting the obtained signal using the following equation:

number

number

[0066] Figure 13(b) shows the result of fitting the fundamental component using Equation 1. Figure 13(c) shows the R AHE , R PHE The second harmonic component was fitted using the FT-IR curve. Both curves were fitted accurately, and the component was resolved into components A and B. The effective magnetic field H DL , H FL The spin Hall angle ξ is given by the following equation: DL , ξ FL It is calculated as:

number

number

[0067] Ru in Example 1 50 Cu 50 The layer is Ru 25 Cu 75 Layer, Ru75 Cu 25 The same structure was fabricated in the same manner, except for the substitution of layers.

[0068] Figure 14(a) shows Ru 25 Cu 75 The stacked structure of Ru is shown in Fig. 14(b). 25 Cu 75 The figure shows the laminated state of the thin film. First, Ru is deposited on about one atomic plane (0.2 nm), and then Cu is deposited on about three atomic planes (0.6 nm). By repeating this structure, a Ru film with a thickness of about 10 nm is formed. 25 Cu 75 A cross-sectional HAADF-STEM image of this laminated structure revealed Ru 25 Cu 75 The layer was a homogeneous polycrystalline film with an FCC structure. Figure 14(c) shows the EDS composition profile in the direction perpendicular to the film surface of this laminated structure. Although there is some fluctuation in the Ru and Cu compositions, the atomic ratio of Ru1:Cu3 is approximately obtained. It can be seen that there is a slightly higher amount of Cu at the NiFe interface, but the Ru 25 Cu 75 No clear atomic diffusion into the Ru layer was observed. 25 Cu 75 Alloying was also achieved with Cu-rich compositions.

[0069] Figure 15(a) shows Ru 75 Cu 25 The stacked structure of Ru is shown in Fig. 15(b). 25 Cu 75 The figure shows the laminated state of the thin film. First, Ru is deposited on about three atomic planes (0.6 nm), and then Cu is deposited on about one atomic plane (0.2 nm). By repeating this structure, a Ru film with a thickness of about 10 nm is formed. 75 Cu 25 The cross-sectional HAADF-STEM image showed that Ru 75 Cu 25 The layer was a homogeneous polycrystalline film with an HCP structure. Figure 15(c) shows the EDS composition profile in the direction perpendicular to the film surface. The Ru and Cu compositions are homogeneous, with the atomic ratio of Ru3:Cu1 being realized throughout the entire region. In this sample as well, the Ni from the NiFe layer and the Ru from Fe were 75 Cu 25No clear atomic diffusion into the Ru layer was observed. 75 Cu 25 Alloying was also achieved in the Ru-rich composition.

[0070] The current density dependence of the USMR signal is shown in Fig. 16. 25 Cu 75 layer, and Fig. 16(c) shows Ru 75 Cu 25 The results are for the Ru layer sample of Example 1 as a reference. 50 Cu 50 The results for the layer are also shown in Figure 16(b). 2 A large value of about 0.5 to 1.5 mΩ is maintained at a current density of 1000 Ω. Therefore, it is understood that the present invention is effective for a wide range of Ru-Cu compositions. 2 O 3 The alloy was also prepared by melting it in a crucible. EXAMPLES

[0071] A 9 nm Ru film was sputtered on a sapphire (0001) substrate at a substrate temperature of 300°C under conditions of Ar gas pressure of 0.1 Pa and DC 40 W. Then, in the same chamber, a post-heat treatment was performed at 550°C for 1 hour. After returning to room temperature, Cu and Ru were laminated 5 times, one atomic plane (0.2 nm each), to form a Ru film with a thickness of about 2 nm. 50 Cu 50 A film was obtained. Then, post-heating was performed under the condition of 300°C for 15 minutes. After the substrate temperature returned to room temperature, NiFe was formed under the same conditions as in Example 1, and then post-heating was performed under the condition of 200°C for 15 minutes. Finally, a Mg layer was formed under the same conditions as in Example 1, and the substrate was taken out of the chamber to the atmosphere to form a MgO protective film.

[0072] The laminated structure shown in FIG. 17(a) is a schematic diagram of the above method. 50 Cu 50 The stacking state of the thin films is shown in Fig. 17(c). 50 Cu 50The HAADF-STEM images of the periphery of the layer are shown. 50 Cu 50 The NiFe layer and the NiFe layer are all epitaxially grown and obtained as single crystal samples. The interfaces between the layers are very smooth. 50 Cu 50 The layer is a repetition of two types of planes, A and B, which indicates that an HCP (0001) structure is obtained. On the other hand, the NiFe layer is a repetition of three types of planes, A', C', and B', which means that an FCC (111) structure is obtained. This shows that a Ru-Cu alloy film can be realized as a single crystal laminated structure with a smooth interface. Figure 17(d) shows the USMR signal measurement result (current density 27 MA / cm) measured after patterning and electrode formation in the same manner as in Example 1. 2 ) is shown. A value (~0.15 mΩ) that is more than one order of magnitude larger than that of the sample using the aforementioned single-phase Ru film (10 nm) is obtained in the saturation region, indicating that the spin Hall effect is also large in the single-crystal Ru-Cu film.

[0073] The present invention should not be interpreted as being limited to the above-mentioned embodiment, and the configuration may be appropriately modified within the scope obvious to those skilled in the art. For example, a non-magnetic layer (assuming a metal film such as Cu or Ti, with a thickness of about 0<thickness≦10 nm) may be inserted between the spin Hall layer and the magnetic layer. This non-magnetic layer provides an improvement effect on the interface. [Industrial Applicability]

[0074] As described above, according to the present invention, it is possible to provide a magnetic laminated film suitable for use in a spin-orbit torque writing type MRAM (SOT-MRAM). The magnetic memory element and magnetic memory of the present invention use a magnetic laminated film in which the spin current generation efficiency is greatly improved by a thin film of alloyed Ru and Cu, so that a high-performance spin-orbit torque writing type MRAM (SOT-MRAM) can be provided, which is suitable for use in a storage device. [Explanation of symbols]

[0075] 10 Channel layer (spin current generation layer) 11 Base layer 12 Interface insertion layer 20 First ferromagnetic layer (magnetic layer) 30 Barrier Layer 40 Reference layer 41 Second ferromagnetic layer 42 Bonding layer 43 Third ferromagnetic layer 50 Cap Tier 60 Plug 70 Substrate 80 Protective layer (MgO layer) 100~105 Magnetic memory element 120X Driver 130 Y driver 140 Controller 200 Magnetic memory cell circuit 210 Magnetic memory cell array 300 Magnetic Memory

Claims

1. A magnetic laminated film for a magnetic memory element, a channel layer for generating a spin current for magnetic reversal; a first ferromagnetic layer adjacent to the channel layer and including a ferromagnetic layer having reversible magnetization; Equipped with The channel layer is made of Ru １－ｘ Cu ｘ (0.10≦x≦0.90), The thickness of the channel layer is in the range of 2 nm to 30 nm. A magnetic laminated film characterized by:

2. The crystal structure of the channel layer is a hexagonal close-packed (HCP) structure in the Ru-rich composition, a face-centered cubic (FCC) structure in the Cu-rich composition, and both the hexagonal close-packed and cubic close-packed structures are present between the Ru-rich and Cu-rich compositions.

2. The magnetic laminated film according to claim 1.

3. The channel layer is made of Ru １－ｘ Cu ｘ (0.25≦x≦0.75), 3. The magnetic laminated film according to claim 1 or 2.

4. a conductive non-magnetic layer interposed between the channel layer and the first ferromagnetic layer; The thickness of the non-magnetic layer is in the range of 0.2 nm to 10 nm.

3. The magnetic laminated film according to claim 1 or 2.

5. further comprising a substrate on which the channel layer and the first ferromagnetic layer are stacked.

3. The magnetic laminated film according to claim 1 or 2.

6. The magnetic multilayer film according to claim 1 or 2; a barrier layer adjacent to the first ferromagnetic layer and made of an insulating material; a reference layer adjacent to the barrier layer and having at least one ferromagnetic layer whose magnetization direction is fixed; a cap layer adjacent to the reference layer and made of a conductive material; a first terminal at one end of the channel layer in the longitudinal direction, through which a current can be introduced; a second terminal at the other end of the channel layer in the longitudinal direction, through which a current can be introduced; a third terminal capable of introducing a current into the cap layer; A magnetic memory element comprising:

7. a fourth terminal connected to the first ferromagnetic layer; 7. The magnetic memory element according to claim 6.

8. The first ferromagnetic layer has a magnetization that can be reversed in a direction perpendicular to the out-of-plane direction of the film surface.

7. The magnetic memory element according to claim 6.

9. the first ferromagnetic layer has a magnetization that can be reversed in a direction perpendicular to a line segment connecting the first terminal and the second terminal within a film plane; 7. The magnetic memory element according to claim 6.

10. the first ferromagnetic layer has a magnetization that can be reversed in a direction parallel to a line segment connecting the first terminal and the second terminal within a film plane; 7. The magnetic memory element according to claim 6.

11. the first ferromagnetic layer has a first magnetization region, and a second magnetization region and a third magnetization region disposed on either side of the first magnetization region; the magnetization of the second magnetization region and the magnetization of the third magnetization region are fixed in different directions from each other, The magnetization of the first magnetization region is reversible and can be oriented in the same direction as either the magnetization of the second magnetization region or the magnetization of the third magnetization region.

7. The magnetic memory element according to claim 6.

12. The magnetic memory element according to claim 6 ; a write means for writing data into the magnetic memory element by passing a write current through the magnetic memory element; a read means for reading data written in the magnetic memory element by passing a current through the barrier layer to determine a tunnel resistance; A magnetic memory comprising:

Images