Spin orbit torque magnetic memory device using magnetic phase transition

Abstract

A spin-orbit torque magnetic memory device comprises a phase transition magnetic layer, a ferromagnetic layer, a non-magnetic conductive layer, and a free magnetic layer. The phase transition magnetic layer generates a first spin current by spin pumping through magnetic phase transition. The ferromagnetic layer is disposed on the phase transition magnetic layer. The ferromagnetic layer comprises a ferromagnet. The non-magnetic conductive layer is disposed on the ferromagnetic layer. The non-magnetic conductive layer comprises a non-magnetic metal. The free magnetic layer is disposed on the non-magnetic conductive layer. When power is supplied to the ferromagnetic layer and the non-magnetic conductive layer, a second spin current is generated at the interface between the non-magnetic conductive layer and the ferromagnetic layer through at least one of the spin Hall effect and the Rashba-Edelstein effect. At least one of the phase transition magnetic layer, the non-magnetic conductive layer, and the ferromagnetic layer is supplied with power to generate heat, and a magnetic phase transition occurs in the phase transition magnetic layer due to the heat. The first spin current and the second spin current are transferred to the free magnetic layer.

Description

Technology Field

[0001] The present invention relates to a spin-orbit torque magnetic memory device (SOT-MRAM). Specifically, the present invention relates to a spin-orbit torque magnetic memory device that significantly improves switching efficiency by utilizing magnetic phase transition. Background Technology

[0002] A spin-orbit torque magnetic memory device is a memory device that stores information using the magnetization direction of a fixed magnetic layer and the magnetization direction of a free magnetic layer. The magnetization direction of the free magnetic layer can be switched by spin-orbit torque (SOT). In other words, the performance of the spin-orbit torque magnetic memory device can be improved as the switching of the magnetization direction of the free magnetic layer becomes easier.

[0003] However, conventional spin-orbit torque magnetic memory devices have a problem in that the current density required to switch the magnetization direction of the free magnetic layer is very high, necessitating the addition of separate devices and circuits to supply it. Accordingly, there is a need for the development of technology that can switch the magnetization direction of the free magnetic layer even at low current densities. The problem to be solved

[0004] The objective of the present invention is to provide a spin-orbit torque magnetic memory device that significantly improves the switching efficiency described above by utilizing a magnetic phase transition. means of solving the problem

[0005] A spin-orbit torque magnetic memory device according to one embodiment of the present invention may include a phase-transition magnetic layer, a ferromagnetic layer, a non-magnetic conductive layer, and a free magnetic layer. The phase-transition magnetic layer may generate a first spin current by spin pumping through magnetic phase transition. The ferromagnetic layer may be disposed on the phase-transition magnetic layer. The ferromagnetic layer may include a ferromagnet. The non-magnetic conductive layer may be disposed on the ferromagnetic layer. The non-magnetic conductive layer may include a non-magnetic metal. The free magnetic layer may be disposed on the non-magnetic conductive layer. When power is supplied to the ferromagnetic layer and the non-magnetic conductive layer, a second spin current may be generated at least one of the spin Hall effect and the Rashba-Edelstein effect at the interface between the non-magnetic conductive layer and the ferromagnetic layer. At least one of the phase transition magnetic layer, the non-magnetic conductive layer, and the ferromagnetic layer is supplied with power to generate heat, and a magnetic phase transition may occur in the phase transition magnetic layer due to the heat. The first spin current and the second spin current may be transferred to the free magnetic layer.

[0006] A spin-orbit torque magnetic memory device according to one embodiment of the present invention may further include a tunnel barrier layer and a fixed magnetic layer. The tunnel barrier layer may be disposed on a free magnetic layer. The tunnel barrier layer may include an insulating material. The fixed magnetic layer may be disposed on the tunnel barrier layer.

[0007] In one embodiment of the present invention, the free magnetic layer and the fixed magnetic layer may each include at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn. The tunnel barrier layer may include at least some of AlOx, MgO, TaOx, and ZrOx.

[0008] In one embodiment of the present invention, the phase transition magnetic layer may include at least one of a ferromagnet and an antiferromagnet.

[0009] In one embodiment of the present invention, the thickness of the phase transition magnetic layer may be longer than the spin dephasing length of each of the ferromagnetism and antiferromagnetism of the phase transition magnetic layer.

[0010] In one embodiment of the present invention, after a magnetic phase transition occurs in the phase transition magnetic layer, the magnetization direction of the phase transition magnetic layer may be parallel to the magnetization direction of the ferromagnetic layer.

[0011] In one embodiment of the present invention, the polarization direction of the first spin current may be parallel to the magnetization direction of the phase transition magnetic layer.

[0012] In one embodiment of the present invention, the ferromagnetic layer can receive at least a portion of the second spin current and generate a third spin current by spin pumping. The third spin current can be transferred to the free magnetic layer.

[0013] In one embodiment of the present invention, the magnetization direction of the free magnetic layer can be switched by at least one of a first spin current, a second spin current, and a third spin current.

[0014] In one embodiment of the present invention, the phase transition magnetic layer may include at least some of Fe, Co, Ni, B, Si, Zr, O, N, Cu, Ta, Pt, W, Hf, Ir, Rh, Pd, Gd, Bi, Ir, and Mn. The ferromagnetic layer may include at least some of Fe, Co, Ni, B, Si, and Zr. The non-magnetic conductive layer may include at least some of Cu, Ta, Pt, W, Ti, and Bi.

[0015] A spin-orbit torque magnetic memory device according to one embodiment of the present invention may include a spin-pumping structure and a magnetic tunnel junction structure. The spin-pumping structure may include a phase-transition magnetic layer, a ferromagnetic layer, and a non-magnetic conductive layer. The magnetic tunnel junction structure may be disposed on the spin-pumping structure. The magnetic tunnel junction structure may include a free magnetic layer, a tunnel barrier layer, and a fixed magnetic layer. At least one of the phase-transition magnetic layer, the non-magnetic conductive layer, and the ferromagnetic layer may generate heat by receiving power. A magnetic phase transition may occur in the phase-transition magnetic layer due to the heat. The phase-transition magnetic layer may generate a first spin current by spin-pumping through the magnetic phase transition. The first spin current may be transferred to the free magnetic layer.

[0016] In one embodiment of the present invention, when power is supplied to a ferromagnetic layer and a nonmagnetic conductive layer, a second spin current may be generated at the interface between the nonmagnetic conductive layer and the ferromagnetic layer through at least one of the Spin Hall Effect and the Rashba-Edelstein Effect. The second spin current may be transmitted to a free magnetic layer.

[0017] In one embodiment of the present invention, the free magnetic layer and the fixed magnetic layer may each include at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn. The tunnel barrier layer may include at least some of AlOx, MgO, TaOx, and ZrOx.

[0018] In one embodiment of the present invention, the phase transition magnetic layer may include at least one of a ferromagnet and an antiferromagnet.

[0019] In one embodiment of the present invention, the thickness of the phase transition magnetic layer may be longer than the spin dephasing length of each of the ferromagnetism and antiferromagnetism of the phase transition magnetic layer.

[0020] In one embodiment of the present invention, after a magnetic phase transition occurs in the phase transition magnetic layer, the magnetization direction of the phase transition magnetic layer may be parallel to the magnetization direction of the ferromagnetic layer.

[0022] In one embodiment of the present invention, the polarization direction of the first spin current may be parallel to the magnetization direction of the phase transition magnetic layer.

[0023] In one embodiment of the present invention, the ferromagnetic layer can receive at least a portion of the second spin current and generate a third spin current by spin pumping. The third spin current can be transferred to the free magnetic layer.

[0024] In one embodiment of the present invention, the magnetization direction of the free magnetic layer can be switched by at least one of a first spin current, a second spin current, and a third spin current.

[0025] In one embodiment of the present invention, the phase transition magnetic layer may include at least some of Fe, Co, Ni, B, Si, Zr, O, N, Cu, Ta, Pt, W, Hf, Ir, Rh, Pd, Gd, Bi, Ir, and Mn. The ferromagnetic layer may include at least some of Fe, Co, Ni, B, Si, and Zr. The non-magnetic conductive layer may include at least some of Cu, Ta, Pt, W, Ti, and Bi. Effects of the invention

[0026] According to one embodiment of the present invention, a spin-orbit torque magnetic memory device with significantly improved switching efficiency described above can be provided by utilizing a magnetic phase transition. Brief explanation of the drawing

[0027] FIG. 1 illustrates an exemplary spin-orbit torque magnetic memory device according to one embodiment of the present invention. FIGS. 2a to 2d are drawings illustrated to explain the process of switching the magnetization direction of a free magnetic layer. FIGS. 3a to 3c are exemplary drawings illustrating spin currents by transverse spin pumping and longitudinal spin pumping in a phase transition magnetic layer. Figures 4a and 4b are diagrams illustrating an experiment to measure the spin current generated by the magnetic phase transition of FeRh. Specific details for implementing the invention

[0028] Preferred embodiments of the present invention will be described in more detail below with reference to the attached drawings. In the drawings, the proportions and dimensions of the components may be exaggerated for the effective explanation of the technical content.

[0029] Terms such as "include" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0030] In addition, when a component is described as "above," it refers to the area above or below the component, and does not necessarily mean that it is located on the upper side relative to the direction of gravity.

[0031] In addition, where it is stated that a component is "connected" or "combined" to another component, this may include not only cases where the component is directly connected or combined to the other component, but also cases where the component is indirectly connected or combined through another component.

[0032] In addition, terms such as "first," "second," etc., may be used to describe a component; however, these terms are intended merely to distinguish the component from other components and are not intended to limit the essence, order, or sequence of the component.

[0033] Preferred embodiments of the present invention will be described in more detail below with reference to the attached drawings. In the drawings, the proportions and dimensions of the components may be exaggerated for the effective explanation of the technical content.

[0034] FIG. 1 illustrates an exemplary spin-orbit torque magnetic memory device (SMM) according to one embodiment of the present invention.

[0035] A spin-orbit torque magnetic memory device (SMM) may include a spin-pumping structure (SPP) and a magnetic tunnel junction structure (MTJ).

[0036] The spin pumping structure (SPP) may include a substrate (BSL), a phase transition magnetic layer (PTL), a ferromagnetic layer (FML), and a non-magnetic conductive layer (CDL).

[0037] The magnetic tunnel junction structure (MTJ) may include a free magnetic layer (FRL), a tunnel barrier layer (TBL), and a fixed magnetic layer (FXL). The magnetic tunnel junction structure (MTJ) may be disposed on a spin pumping structure (SPP).

[0038] In this specification, magnetization may refer to the magnetic moment possessed by an object. A spin-orbit torque magnetic memory device (SMM) may be a memory device that stores information using the magnetization direction (MM1) of a free magnetic layer and the magnetization direction (MM2) of a fixed magnetic layer.

[0039] A phase transition magnetic layer (PTL) can be disposed on a substrate (BSL). For example, the phase transition magnetic layer (PTL) may include at least some of Fe, Co, Ni, B, Si, Zr, O, N, Cu, Ta, Pt, W, Hf, Ir, Rh, Pd, Gd, Bi, Ir, and Mn.

[0040] A ferromagnetic layer (FML) can be disposed on a phase transition magnetic layer (PTL). The ferromagnetic layer (FML) may contain ferromagnetism. For example, the ferromagnetic layer (FML) may contain at least some of Fe, Co, Ni, B, Si, and Zr.

[0041] A non-magnetic conductive layer (CDL) may be disposed on a ferromagnetic layer (FML). The non-magnetic conductive layer (CDL) may include a non-magnetic metal. For example, the non-magnetic conductive layer (CDL) may include at least some of Cu, Ta, Pt, W, Ti, and Bi.

[0042] A free magnetic layer (FRL) can be disposed on a non-magnetic conductive layer (CDL). For example, the free magnetic layer (FRL) may include at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn.

[0043] The tunnel barrier layer (TBL) is disposed on the free magnetic layer (FRL) and may include an insulating material. In one embodiment of the present invention, the tunnel barrier layer (TBL) may be omitted. For example, the tunnel barrier layer (TBL) may include at least some of AlOx, MgO, TaOx, and ZrOx.

[0044] A fixed magnetic layer (FXL) may be disposed on a tunnel barrier layer (TBL). In one embodiment of the present invention, the fixed magnetic layer (FXL) may be omitted. For example, the fixed magnetic layer (FXL) may include at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn.

[0045] FIGS. 2a to 2d are drawings illustrated to explain the process of switching the magnetization direction (MM1) of the free magnetic layer (FRL).

[0046] Referring to FIG. 2a, the magnetization direction (MM1) of the free magnetic layer (FRL) may be a second direction (DR2). Each of the non-magnetic conductive layer (CDL), the ferromagnetic layer (FML), and the phase transition magnetic layer (PTL) contains a conductive material, and a first in-plane current (CR1), a second in-plane current (CR2), and a third in-plane current (CR3) may flow through the non-magnetic conductive layer (CDL), the ferromagnetic layer (FML), and the phase transition magnetic layer (PTL), respectively. When power is supplied through the first in-plane current (CR1), the second in-plane current (CR2), and the third in-plane current (CR3), the phase transition non-magnetic conductive layer (CDL), the ferromagnetic layer (FML), and the phase transition magnetic layer (PTL) may generate heat.

[0047] Referring to Fig. 2b, a magnetic phase transition can occur in the phase transition magnetic layer (PTL) due to heat generated in the non-magnetic conductive layer (CDL) and the ferromagnetic layer (FML). A magnetic phase transition refers to a phenomenon in which the alignment of spins within a material changes abruptly due to external factors. During the magnetic phase transition process, spin currents are generated by transverse spin pumping and longitudinal spin pumping, and the magnitude of the spin current can correspond to the difference in net magnetization. Transverse spin pumping and longitudinal spin pumping are explained in detail in Figs. 3b and 3c.

[0048] The phase transition magnetic layer (PTL) can generate a first spin current (SPC1) by spin pumping through a magnetic phase transition. Additionally, when power is supplied to the ferromagnetic layer (FML) and the nonmagnetic conductive layer (CDL), a second spin current (SPC2) can be generated at the interface between the nonmagnetic conductive layer (CDL) and the ferromagnetic layer (FML) through at least one of the spin Hall effect and the Rashba-Edelstein effect.

[0049] In one embodiment of the present invention, when power is supplied to the phase transition magnetic layer (PTL), the ferromagnetic layer (FML), and the nonmagnetic conductive layer (CDL), a second spin current (SPC2) can be generated by the magnetized spin Hall effect in the ferromagnetic layer (FML), the spin Hall effect in the nonmagnetic conductive layer (CDL), the spin Hall effect and the Rashba-Edelstein effect at the interface between the ferromagnetic layer (FML) and the nonmagnetic conductive layer (CDL), and spin pumping in the phase transition magnetic layer (PTL).

[0050] The Spin Hall Effect refers to the phenomenon in which electrons with opposite spins are separated due to spin-orbit coupling when an electric current flows. The Rashba-Edelstein Effect refers to the phenomenon in which spins align in a specific direction when an electric current flows in a non-centrosymmetric system.

[0051] The first spin current (SPC1) and the second spin current (SPC2) are transferred to the free magnetic layer (FRL) and can contribute to the switching of the magnetization direction (MM1) of the free magnetic layer (FRL). Accordingly, the switching efficiency of the spin-orbit torque magnetic memory device (SMM) can be improved.

[0052] In one embodiment of the present invention, the phase transition magnetic layer (PTL) may include at least one of a ferromagnet and an antiferromagnet. However, the phase transition magnetic layer (PTL) of the present invention is not limited thereto, and it is sufficient for the phase transition magnetic layer (PTL) to react to heat to cause a magnetic phase transition and generate a spin current by spin pumping.

[0053] Referring to FIG. 2c, in one embodiment of the present invention, the ferromagnetic layer (FML) can receive at least a portion of the second spin current (SPC2) and generate a third spin current (SPC3) by spin pumping. The third spin current (SPC3) can be transferred to the free magnetic layer (FRL) and contribute to switching the magnetization direction (MM1) of the free magnetic layer (FRL).

[0054] Referring to FIG. 2a and FIG. 2d, the magnetization direction (MM1) of the free magnetic layer (FRL) can be switched from the second direction (DR2) to the first direction (DR1) by at least one of the first spin current (SPC1), the second spin current (SPC2), and the third spin current (SPC3).

[0055] FIGS. 3a to 3c are exemplary drawings illustrating spin currents by transverse spin pumping and longitudinal spin pumping in a phase transition magnetic layer (PTL).

[0056] Hereinafter, spin currents generated by transverse spin pumping and longitudinal spin pumping in a phase transition magnetic layer (PTL) are explained with reference to [Equation 1] to [Equation 4].

[0057] In this specification, a ferromagnet refers to a material that spontaneously magnetizes without the application of a strong external magnetic field. The equation of motion for magnetization of a ferromagnet may be [Equation 1].

[0058] [Mathematical Formula 1]

[0059]

[0060] is the magnetization unit vector, and is the gyromagnetic ratio, and is the effective magnetic field vector, and ε₀ can be the Gilbert damping constant. [Equation 1] relates to transverse magnetization dynamics that exhibit precession with respect to an effective magnetic field while the magnitude of the magnetic moment is fixed.

[0061] Transverse spin-pumping current induced from transverse magnetization motion It can be defined by [Mathematical Formula 2].

[0062] [Mathematical Formula 2]

[0063]

[0064] is the Dirac constant ) and is the interfacial spin-mixing conductance. The spin current due to transverse spin pumping can have a spin component perpendicular to the magnetization unit vector.

[0065] axial spin-pumping current induced from axial magnetization motion It can be defined as [Mathematical Formula 3].

[0066] [Mathematical Formula 3]

[0067]

[0068] is interface conductance and is the magnitude of the magnetic moment It could be. represents the rate of change of the magnitude of an individual magnetic moment, and the rate of change of the magnitude of an individual magnetic moment is distinguished from the situation where the sum of multiple magnetic moments changes. When multiple magnetic moments undergo precession, the magnitude of the net magnetization may decrease because the magnetic moments are not parallel to each other. The spin current due to longitudinal spin pumping has a component parallel to the magnetization unit vector.

[0069] Transverse magnetization motion has classical characteristics, whereas longitudinal magnetization motion has quantum mechanical characteristics. Spin pumping is the spin of a conduction electron. and local spin moments It is derived from the sd-exchange interaction between them and can be expressed as [Equation 4].

[0070] [Mathematical Formula 4]

[0071]

[0072] and Is and It is the spin creation / destruction operator. is a component that represents the spin-transfer torque and its onsager reciprocal, transverse spin pumping. Is and It is a component that expresses the quantum fluctuation of, and the antiparallel induced by this and The spin transfer torque between them is called Quantum Spin Transfer. Since longitudinal spin pumping is inversely related to Quantum Spin Transfer, it is a phenomenon that reflects the quantum mechanical characteristics of exchange interactions.

[0073] Spin currents can be generated in the phase transition magnetic layer (PTL) by transverse spin pumping and longitudinal spin pumping. After a magnetic phase transition occurs in the phase transition magnetic layer (PTL), the magnetization direction (MM3) of the phase transition magnetic layer can become parallel to the magnetization direction (MM4) of the ferromagnetic layer through exchange interaction.

[0074] The polarization direction of the spin current due to transverse spin pumping is perpendicular to the magnetization direction (MM3) of the magnetic layer, and the polarization direction of the spin current due to longitudinal spin pumping can be parallel to the magnetization direction (MM3) of the magnetic layer.

[0075] Referring to FIG. 3a, the polarization direction of the first spin current (SPC1) may be parallel to the magnetization direction (MM3) of the phase transition magnetic layer and the magnetization direction (MM4) of the ferromagnetic layer. That is, the first spin current (SPC1) may be a spin current produced by longitudinal spin pumping.

[0076] In one embodiment of the present invention, the thickness (TH) of the ferromagnetic layer may be longer than the spin dephasing length of the ferromagnetism and antiferromagnetism, respectively, of the phase transition magnetic layer (PTL). If the thickness (TH) of the ferromagnetic layer is longer than the spin dephasing length, the switching efficiency can be significantly improved. This will be explained below using FIGS. 3b and 3c.

[0077] Figure 3b is a graph showing the distribution of spin current generated by transverse spin pumping, and Figure 3c is a graph showing the distribution of spin current generated by longitudinal spin pumping.

[0078] Referring to FIG. 3b, the spin current (AA) generated by transverse spin pumping is completely attenuated within the ferromagnetic metal and cannot be transmitted to the normal metal. On the other hand, the spin current (BB) generated at the interface between the ferromagnetic metal and the normal metal is not completely attenuated and can therefore be transmitted to the normal metal. Specifically, the spin current generated by transverse spin pumping is attenuated within the spin dephasing length, so it cannot be transmitted to the outside once it extends beyond the spin dephasing length.

[0079] Therefore, when attempting to switch the magnetization direction (MM1) of the free magnetic layer (FRL) using the spin current generated by transverse spin pumping in the phase transition magnetic layer (PTL), the thickness (TH) of the ferromagnetic layer must be smaller than the spin dephasing length. However, there is a problem in that if the thickness (TH) of the ferromagnetic layer is reduced, the amount of spin current generated through spin pumping in the ferromagnetic layer (FML) decreases, and thus the switching efficiency cannot be sufficiently improved.

[0080] On the other hand, referring to Fig. 3c, the spin current (CC) due to longitudinal spin pumping is not entirely attenuated within the ferromagnetic metal and can therefore be transferred to the normal metal. Specifically, the spin current due to longitudinal spin pumping is attenuated within the spin diffusion length, and the spin diffusion length is generally longer than the spin dephasing length.

[0081] Therefore, when switching the magnetization direction (MM1) of the free magnetic layer (FRL) using the spin current generated by longitudinal spin pumping in the phase transition magnetic layer (PTL), the thickness (TH) of the ferromagnetic layer can be secured by a spin diffusion length that is longer than the spin dephasing length. If the thickness (TH) of the ferromagnetic layer is secured further, the amount of spin current generated through spin pumping increases, and the switching efficiency can be improved more.

[0082] Figures 4a and 4b are diagrams illustrating an experiment to measure the spin current generated by the magnetic phase transition of FeRh.

[0083] Referring to FIGS. 4a and FIGS. 4b, As, voltage pulse in FeRh (100 nm), Pt (5 nm) structure Oscilloscope voltage due to magnetic phase transition induced by External magnetic field It is a component that depends on. In this case, the magnitude of the applied external magnetic field The signal satisfies the symmetry condition when the generated spin current is measured as the inverse spin Hall effect at Pt.

[0084] It is the resistance obtained by subtracting the FeRh / Pt resistance below the threshold voltage from the FeRh / Pt resistance above the threshold voltage that causes a self-phase transition. That is, indicates that the resistance changes as FeRh transitions from the antiferromagnetic phase to the ferromagnetic phase. Experimental results, This rapidly changing point and Since the point where the maximum value appears coincides, the signal is due to the spin current caused by the magnetic phase transition.

[0085] Measured The maximum value of is as , when converted to an inverse spin Hall electric field This corresponds to the value. This is at least two orders of magnitude larger than the inverse spin Hall electric field estimated from spin pumping or the spin Seebeck effect generated through ferromagnetic resonance of about 10 GHz [Phys. Rev. B. 82, 214403 (2010); Phys. Rev. B 85, ​​144408 (2012); Phys. Rev. Lett. 112, 197201 (2014); Nature 455, 778 (2008)]. In other words, spin pumping through magnetic phase transition can generate a significantly enhanced spin current compared to conventional spin pumping.

[0086] The contribution of longitudinal magnetization motion to the above magnetic phase transition process and the subsequent spin current generation can be confirmed through the amount of spin generated. The amount of spin per unit area emitted from FeRh to Pt is approximately The net change in local spin of FeRh per unit volume is saturation magnetization It can be derived from, and this quantity is is. Therefore, the effective thickness of FeRh is This is the spin dephase length of FeRh It is about 7 times thicker than [J. Phys. F: Met. Phys. 12, 1123 (1982)]. That is, if only transverse spin pumping exists, the spin current generated in FeRh at a distance of more than 1.4 nm from the FeRh / Pt interface cannot reach Pt. Therefore, the magnetic phase transition phenomenon is accompanied by longitudinal magnetization motion, and through longitudinal spin pumping, a spin current several times larger than that of conventional transverse spin pumping can be generated.

[0087] Therefore, spin-orbit torque structures containing phase-transition magnetic layers can generate significantly enhanced spin currents due to magnetic phase-transition effects, along with the spin Hall effect or the Rashba-Edelstein effect, and quantum mechanical advantages can be expected, particularly because they involve longitudinal spin pumping.

[0088] Although the invention has been described with reference to exemplary embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as set forth in the following claims. Furthermore, the exemplary embodiments disclosed in the invention are not intended to limit the technical spirit of the invention, and all technical spirits within the scope of the following claims and their equivalents should be interpreted as being included within the scope of the rights of the invention. Explanation of the symbols

[0089] MMD: Spin-orbit Torque Magnetic Memory Device FXL: Fixed magnetic layer TBL: Tunnel barrier layer FRL: Free magnetic layer CDL: Non-magnetic conductive layer FML: Ferromagnetic layer PTL: Phase transition magnetic layer BSL: Substrate

Claims

Claim 1 A phase transition magnetic layer that generates a first spin current by spin pumping through a magnetic phase transition; a ferromagnetic layer disposed on the phase transition magnetic layer and comprising a ferromagnet; and a non-magnetic conductive layer disposed on the ferromagnetic layer and comprising a non-magnetic metal. A spin-orbit torque magnetic memory device comprising a free magnetic layer disposed on the non-magnetic conductive layer, wherein when power is supplied to the ferromagnetic layer and the non-magnetic conductive layer, a second spin current is generated through at least one of the Spin Hall Effect and the Rashba-Edelstein Effect at the interface between the non-magnetic conductive layer and the ferromagnetic layer, and at least one of the phase transition magnetic layer, the non-magnetic conductive layer, and the ferromagnetic layer receives power to generate heat, and the magnetic phase transition occurs in the phase transition magnetic layer due to the heat, and the first spin current and the second spin current are transferred to the free magnetic layer. Claim 2 A spin-orbit torque magnetic memory device according to claim 1, further comprising: a tunnel barrier layer disposed on the free magnetic layer and comprising an insulating material; and a fixed magnetic layer disposed on the tunnel barrier layer. Claim 3 A spin-orbit torque magnetic memory device according to claim 2, wherein each of the free magnetic layer and the fixed magnetic layer comprises at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn, and the tunnel barrier layer comprises at least some of AlOx, MgO, TaOx, and ZrOx. Claim 4 In claim 1, the phase transition magnetic layer comprises at least one of a ferromagnet and an antiferromagnet. Claim 5 A spin-orbit torque magnetic memory device in which the thickness of the phase transition magnetic layer is longer than the spin dephasing length of each of the ferromagnetism and antiferromagnetism of the phase transition magnetic layer. Claim 6 A spin-orbit torque magnetic memory device according to claim 1, wherein after the magnetic phase transition occurs in the phase transition magnetic layer, the magnetization direction of the phase transition magnetic layer is parallel to the magnetization direction of the ferromagnetic layer. Claim 7 In claim 6, the spin-orbit torque magnetic memory device in which the polarization direction of the first spin current is parallel to the magnetization direction of the phase transition magnetic layer. Claim 8 A spin-orbit torque magnetic memory device according to claim 1, wherein the ferromagnetic layer receives at least a portion of the second spin current to generate a third spin current by spin pumping, and the third spin current is transmitted to the free magnetic layer. Claim 9 In claim 8, the magnetization direction of the free magnetic layer is switched by at least one of the first spin current, the second spin current, and the third spin current in a spin-orbit torque magnetic memory device. Claim 10 A spin-orbit torque magnetic memory device according to claim 1, wherein the phase transition magnetic layer comprises at least some of Fe, Co, Ni, B, Si, Zr, O, N, Cu, Ta, Pt, W, Hf, Ir, Rh, Pd, Gd, Bi, Ir, and Mn, the ferromagnetic layer comprises at least some of Fe, Co, Ni, B, Si, and Zr, and the non-magnetic conductive layer comprises at least some of Cu, Ta, Pt, W, Ti, and Bi. Claim 11 A spin-orbit torque magnetic memory device comprising: a spin-pumping structure including a phase-transition magnetic layer, a ferromagnetic layer, and a non-magnetic conductive layer; and a magnetic tunnel junction structure disposed on the spin-pumping structure and including a free magnetic layer, a tunnel barrier layer, and a fixed magnetic layer, wherein at least one of the phase-transition magnetic layer, the non-magnetic conductive layer, and the ferromagnetic layer receives power to generate heat, and a magnetic phase transition occurs in the phase-transition magnetic layer due to the heat, and the phase-transition magnetic layer generates a first spin current by spin-pumping through the magnetic phase transition, and the first spin current is transmitted to the free magnetic layer. Claim 12 A spin-orbit torque magnetic memory device according to claim 11, wherein when power is supplied to the ferromagnetic layer and the nonmagnetic conductive layer, a second spin current is generated at least one of the Spin Hall Effect and the Rashba-Edelstein Effect at the interface between the nonmagnetic conductive layer and the ferromagnetic layer, and the second spin current is transmitted to the free magnetic layer. Claim 13 A spin-orbit torque magnetic memory device according to claim 11, wherein each of the free magnetic layer and the fixed magnetic layer comprises at least some of Fe, Co, Ni, B, Si, Zr, Tb, and Mn, and the tunnel barrier layer comprises at least some of AlOx, MgO, TaOx, and ZrOx. Claim 14 In claim 11, the phase transition magnetic layer comprises at least one of a ferromagnet and an antiferromagnet. Claim 15 A spin-orbit torque magnetic memory device in which the thickness of the phase transition magnetic layer is longer than the spin dephasing length of each of the ferromagnetism and antiferromagnetism of the phase transition magnetic layer. Claim 16 In claim 11, a spin-orbit torque magnetic memory device in which, after the magnetic phase transition occurs in the phase transition magnetic layer, the magnetization direction of the phase transition magnetic layer is parallel to the magnetization direction of the ferromagnetic layer. Claim 17 In claim 16, the spin-orbit torque magnetic memory device in which the polarization direction of the first spin current is parallel to the magnetization direction of the phase transition magnetic layer. Claim 18 In claim 12, the ferromagnetic layer receives at least a portion of the second spin current to generate a third spin current by spin pumping, and the third spin current is transferred to the free magnetic layer, forming a spin-orbit torque magnetic memory device. Claim 19 In claim 18, the magnetization direction of the free magnetic layer is switched by at least one of the first spin current, the second spin current, and the third spin current in a spin-orbit torque magnetic memory device. Claim 20 A spin-orbit torque magnetic memory device according to claim 11, wherein the phase transition magnetic layer comprises at least some of Fe, Co, Ni, B, Si, Zr, O, N, Cu, Ta, Pt, W, Hf, Ir, Rh, Pd, Gd, Bi, Ir, and Mn, the ferromagnetic layer comprises at least some of Fe, Co, Ni, B, Si, and Zr, and the non-magnetic conductive layer comprises at least some of Cu, Ta, Pt, W, Ti, and Bi.

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