Spin torque diode power supply

Abstract

This spin torque diode power supply has a plurality of groups. Each of the plurality of groups has a plurality of magnetoresistive effect elements connected to satisfy at least one of a series and a parallel relationship. The magnetoresistive effect elements belonging to the same group have a constant aspect ratio of their major axis length to their minor axis length when viewed in a planar view from the stacking direction. The magnetoresistive effect elements belonging to different groups have different aspect ratios of their major axis length to their minor axis length when viewed in a planar view from the stacking direction.

Description

[Technical Field]

[0001] The present disclosure relates to spin torque diode power supplies. [Background technology]

[0002] Semiconductor devices are used in a variety of electronic devices. They operate by controlling the movement of electrons. Spin devices are attracting attention as an alternative to semiconductor devices.

[0003] Spin devices are devices that utilize spintronics. Spintronics is a term coined from the words "spin" and "electronics," and aims to industrially utilize both the charge and spin of electrons. For example, magnetic heads that use tunneling magnetoresistance elements, magnetoresistive random access memories (MRAM) that use spin-transfer magnetization reversal, and high-frequency filters that use spin-transfer self-oscillation are known as spin devices.

[0004] As one type of spin device, a spin torque diode is being investigated (for example, Non-Patent Document 1). A spin torque diode utilizes the property of a magnetoresistive element to rectify high-frequency current. When a high-frequency signal is applied to the magnetoresistive element, the magnetoresistive element generates a DC voltage. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Raghav Sharma et al., nature electronics 7, 653-661 (20254): https: / / doi.org / 10.1038 / s41928-024-01212-1. Summary of the Invention [Problem to be solved by the invention]

[0006] A spin torque diode is an element that can convert a high-frequency signal into a DC voltage. The high-frequency signal vibrates the magnetization of a magnetoresistive element, and the vibration of the magnetization generates a DC voltage in the magnetoresistive element. However, the resonant frequency of the magnetization of the magnetoresistive element has a large Q value, which means that the spin torque diode does not function outside of a specific frequency band.

[0007] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a spin torque diode power supply that can operate at a wide frequency bandwidth. [Means for solving the problem]

[0008] To solve the above problems, the present disclosure provides the following means.

[0009] A spin torque diode power supply according to a first aspect has a plurality of groups. Each of the plurality of groups has a plurality of magnetoresistive effect elements connected to satisfy at least one of a series and a parallel relationship. The magnetoresistive effect elements belonging to the same group have a constant aspect ratio of their major axis length to their minor axis length when viewed in a planar view from the stacking direction. The magnetoresistive effect elements belonging to different groups have different aspect ratios of their major axis length to their minor axis length when viewed in a planar view from the stacking direction. [Effects of the Invention]

[0010] The spin torque diode power supply according to the above aspect has a wide operating frequency bandwidth. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram of a spin torque diode power supply according to the first embodiment. [Figure 2] FIG. 1 is a plan view of a power generating device of a spin torque diode power supply according to a first embodiment. [Figure 3] FIG. 2 is a perspective view of the vicinity of a power generating device of a spin torque diode power supply according to the first embodiment. [Figure 4]1 is a cross-sectional view of the vicinity of a power generating device of a spin torque diode power supply according to a first embodiment. [Figure 5] FIG. 10 is a plan view of a power generating device of a spin torque diode power supply according to a second embodiment. [Figure 6] FIG. 10 is a plan view of a power generating device of a spin torque diode power supply according to a third embodiment. [Figure 7] FIG. 10 is a plan view of a power generating device of a spin torque diode power supply according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present embodiment will be described in detail below with reference to the accompanying drawings. The drawings used in the following description may show characteristic portions enlarged for ease of understanding, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present disclosure is not limited thereto. Appropriate modifications can be made within the scope of the present disclosure.

[0013] First, directions are defined. One direction of the surface on which the magnetoresistive effect element is placed is defined as the X direction, and the direction perpendicular to the X direction within the same surface is defined as the Y direction. The X direction may be, for example, the long axis direction of the magnetoresistive effect element. The X direction may be an example of a first direction. The Y direction may be, for example, the short axis direction of the magnetoresistive effect element. The Y direction may be an example of a second direction. The direction perpendicular to the XY plane is defined as the Z direction. The Z direction may be, for example, the stacking direction of the magnetoresistive effect element. In this specification, "upper" and "lower" may be used, but these expressions refer to the positional relationship with respect to a reference plane and do not define the direction of gravity.

[0014] In this specification, "extending in the X direction" means, for example, that the dimension in the X direction is larger than the smallest dimension among the dimensions in the X direction, Y direction, and Z direction. The same applies to extending in other directions.

[0015] "First embodiment" 1 is a schematic diagram of a spin torque diode power supply according to Embodiment 1. The spin torque diode power supply 1000 includes a power generation device 101, an output device 201, and a high frequency application device 301.

[0016] The power generation device 101 is a part that generates power by utilizing the spin torque diode effect. The output device 201 is connected to the power generation device 101 via a first terminal 111 and a second terminal 112. The output device 201 is a part that outputs a DC voltage generated in the power generation device 101 to the outside. The output device 201 is separable from the power generation device 101. The configuration of the output device 201 can be changed depending on the device connected to the output device 201.

[0017] The output device 201 includes, for example, a capacitor 211 and a converter 212. The capacitor 211 is connected to the first terminal 111 and the second terminal 112. The capacitor 211 holds the DC voltage output from the power generation device 101. The converter 212 is connected to the capacitor 211. The converter 212 converts the DC voltage output from the power generation device 101 into a DC voltage appropriate for a connected device. For example, the converter 212 boosts the DC voltage output from the power generation device 101.

[0018] It is preferable that the output device 201 be impedance-matched to, for example, the power generation device 101. By matching the impedance between the output device 201 and the power generation device 101, it is possible to reduce power loss between the power generation device 101 and the output device 201. For example, the impedance between the first terminal 111 and the second terminal 112 of the power generation device 101 may be 50Ω±25Ω, and the impedance of the output device 201 may be 50Ω±25Ω.

[0019] The high frequency application device 301 is configured to be able to apply a high frequency signal to the power generation device 101. If a high frequency signal can be applied directly to the power generation device 101, the high frequency application device 301 may be omitted.

[0020] The high frequency application device 301 has, for example, an antenna 311 and an antenna wiring 312. The antenna 311 receives a high frequency signal. The high frequency signal may be an electric wave, a magnetic field, or the like, and the type does not matter. For example, the antenna 311 may receive an ultra-high frequency wave in the 2.4 GHz band. The antenna wiring 312 carries the high frequency signal received by the antenna 311 to the vicinity of the power generation device 101. There may be one or more antenna wirings 312. For example, the antenna wiring 312 propagates a high frequency current. The antenna wiring 312 is configured, for example, so that a magnetic field generated from the antenna wiring 312 can be applied to the magnetoresistance effect element of the power generation device 101.

[0021] FIG. 2 is a plan view of the power generating device 101 of the spin torque diode power supply 1000 according to this embodiment.

[0022] The power generating device 101 has a plurality of magnetoresistance effect elements 10, 20, and 30. The power generating device 101 can be divided into a plurality of groups G1, G2, and G3. Here, an example is shown in which three groups G1, G2, and G3 are used, but the number of groups into which the power generating device 101 is divided is not particularly limited.

[0023] The groups G1, G2, and G3 are connected in series or in parallel between the first terminal 111 and the second terminal 112.

[0024] The multiple groups G1, G2, and G3 are arranged, for example, in the X direction. The X direction is, for example, the average direction of the major axis directions of the magnetoresistive effect elements 10, 20, and 30 in the power generating device 101. For example, if the major axis directions of all the magnetoresistive effect elements 10, 20, and 30 are in exactly the same direction, the major axis directions coincide with the X direction.

[0025] The leakage magnetic field from each of the magnetoresistive elements 10, 20, and 30 tends to occur in the X direction. This is because the magnetization of the ferromagnetic layer of each of the magnetoresistive elements 10, 20, and 30 is oriented in the long axis direction of the magnetoresistive elements 10, 20, and 30, and magnetic flux lines tend to occur in the X direction. On the other hand, the magnetization of each of the magnetoresistive elements 10, 20, and 30 tends to oscillate when a magnetic field is applied in the Y direction. When each of the groups G1, G2, and G3 is aligned in the X direction, the leakage magnetic field from each of the groups G1, G2, and G3 mainly occurs in the X direction, which reduces the influence on the other groups G1, G2, and G3.

[0026] Each of the multiple groups G1, G2, and G3 has multiple magnetoresistive effect elements 10, 20, and 30. For example, the group G1 has multiple magnetoresistive effect elements 10, the group G2 has multiple magnetoresistive effect elements 20, and the group G3 has multiple magnetoresistive effect elements 30.

[0027] In groups G1, G2, and G3, the magnetoresistive effect elements 10, 20, and 30 are connected to satisfy at least one of a series and a parallel connection. For example, in group G1, the magnetoresistive effect elements 10 may be connected only in series, only in parallel, or in series-parallel as shown in FIG. 2. The same applies to the other groups.

[0028] The magnetoresistive effect elements 10, 20, and 30 belonging to the same groups G1, G2, and G3 have a constant aspect ratio. For example, the magnetoresistive effect elements 10 belonging to group G1 all have the same aspect ratio. For example, the magnetoresistive effect elements 20 belonging to group G2 all have the same aspect ratio. For example, the magnetoresistive effect elements 30 belonging to group G3 all have the same aspect ratio.

[0029] The magnetoresistive elements 10, 20, and 30 belonging to different groups G1, G2, and G3 have different aspect ratios. For example, the magnetoresistive element 10 belonging to group G1 has a different aspect ratio from the magnetoresistive elements 20 and 30 belonging to other groups G2 and G3.

[0030] The aspect ratio is the ratio of the major axis length to the minor axis length when the magnetoresistive effect elements 10, 20, and 30 are viewed in plan from the Z direction. The aspect ratio can be obtained by dividing the major axis length by the minor axis length. When the plan view shape of the magnetoresistive effect elements 10, 20, and 30 is circular, the major axis length and the minor axis length cannot be defined. In this case, the aspect ratio is defined as the ratio of the length in any one direction to the length orthogonal to that direction. When the plan view shape of the magnetoresistive effect element is circular, the aspect ratio is 1.

[0031] For example, in the example shown in FIG. 2, the aspect ratio of the magnetoresistive effect element 10 of group G1 is L1 / S1, the aspect ratio of the magnetoresistive effect element 20 of group G2 is L2 / S2, and the aspect ratio of the magnetoresistive effect element 30 of group G3 is L3 / S3. L1 / S1, L2 / S2, and L3 / S3 do not match. L1 / S1, L2 / S2, and L3 / S3 satisfy, for example, the relationship L1 / S1 < L2 / S2 < L3 / S3.

[0032] The aspect ratio of the magnetoresistive effect element 10 of group G1 is closer to 1 than the aspect ratios of the magnetoresistive effect elements 20 and 30 of the other groups G2 and G3. In this case, it is preferable that the minor axis length S1 of the magnetoresistive effect element 10 is longer than the minor axis length S2 of the magnetoresistive effect element 20 and the minor axis length S1 of the magnetoresistive effect element 30.

[0033] Also, the aspect ratio of the magnetoresistive effect element 20 of group G2 is closer to 1 than the aspect ratio of the magnetoresistive effect element 30 of group G3. In this case, it is preferable that the minor axis length S2 of the magnetoresistive effect element 20 is longer than the minor axis length S3 of the magnetoresistive effect element 30.

[0034] By ensuring that there is not a large difference in the areas of the magnetoresistive effect elements 10, 20, and 30 that make up each of the groups G1, G2, and G3, it is possible to reduce the difference in element resistance between each of the magnetoresistive effect elements 10, 20, and 30. By reducing the difference in element resistance between each of the magnetoresistive effect elements 10, 20, and 30, it is possible to prevent unevenness in power generation efficiency caused by the frequency of the high-frequency signal applied to the spin torque diode power supply 1000.

[0035] The major axes of the magnetoresistive elements 10, 20, and 30 are preferably aligned in the X direction. Aligning the major axes in the X direction means that the angle between the X direction and the major axes of the magnetoresistive elements 10, 20, and 30 is 45° or less.

[0036] The minor axes of the magnetoresistive elements 10, 20, and 30 are preferably aligned in the Y direction. The minor axes aligned in the Y direction means that the angle between the Y direction and the minor axes of the magnetoresistive elements 10, 20, and 30 is 45° or less.

[0037] In each of the groups G1, G2, and G3, the distance L between the magnetoresistive effect elements 10, 20, and 30 adjacent to each other in the X direction is X is the distance L between the magnetoresistive effect elements 10, 20, and 30 adjacent in the Y direction. Y It may be narrower. Distance L X and distance L Y is the distance between the centers of the magnetoresistive elements 10, 20, and 30 that belong to the same group G1, G2, and G3.

[0038] The leakage magnetic field from each of the magnetoresistive elements 10, 20, and 30 is likely to occur in the X direction. This is because the magnetization of the ferromagnetic layer of each of the magnetoresistive elements 10, 20, and 30 is oriented in the long axis direction of the magnetoresistive elements 10, 20, and 30, and magnetic flux lines are likely to occur in the X direction. XIf the magnetoresistive effect elements are close enough, leakage magnetic flux from adjacent magnetoresistive effect elements joins together, forming a large magnetic flux that connects the magnetoresistive effect elements 10, 20, and 30 aligned in the X direction. The convergence of magnetic flux from the magnetoresistive effect elements 10, 20, and 30 that belong to the same groups G1, G2, and G3 makes it easier for the magnetoresistive effect elements 10, 20, and 30 to resonate.

[0039] Fig. 3 is a perspective view of the vicinity of the power generating device 101 of the spin torque diode power supply 1000 according to this embodiment. Fig. 4 is a cross-sectional view of the vicinity of the power generating device 101 of the spin torque diode power supply 1000 according to this embodiment. Figs. 3 and 4 show a part of group G2 of the power generating device 101, but the specific configurations other than the planar shape of the magnetoresistive effect elements are the same in groups G1 and G3 other than group G2, and therefore description thereof will be omitted.

[0040] The multiple magnetoresistive effect elements 20 are electrically connected by bottom wiring 21, top wiring 22, and via wiring 23. In group G2, the magnetoresistive effect elements aligned in the Y direction are connected in series by top wiring 22 and via wiring 23. When the wiring is connected in the short axis direction rather than the long axis direction, the easy axis of magnetization is aligned with the magnetic field generated when a current flows, and the frequency shift due to the magnetic field is proportional to the amount of current. Therefore, when high-frequency waves are applied, the frequency shifts up and down around the zero-magnetic-field resonance frequency, widening the effective half-width of the resonance frequency and facilitating power generation. Furthermore, when the wiring is connected in the long axis direction rather than the short axis direction, the hard axis of magnetization is aligned with the magnetic field generated when a current flows, and when high-frequency waves are applied, the frequency shifts less from the zero-magnetic-field resonance frequency, facilitating stable power generation.

[0041] The lower wiring 21, the upper wiring 22, and the via wiring 23 may be made of any material as long as they are conductive.

[0042] For example, an antenna wiring 312 is formed near the magnetoresistive effect element 20. The antenna wiring 312 is insulated from the magnetoresistive effect element 20. The antenna wiring 312 is configured so that a voltage can be applied to at least one of the magnetoresistive effect elements 20. The antenna wiring 312 is located above the magnetoresistive effect element 20 in the Z direction, for example.

[0043] The antenna wiring 312 extends, for example, in the X direction. The antenna wiring 312 is arranged, for example, so as to follow the magnetoresistive effect elements 20 lined up in the X direction. When a high-frequency current is applied to the antenna wiring 312, a high-frequency magnetic field is generated around the antenna wiring 312, and the high-frequency magnetic field is applied to the magnetoresistive effect element 20. The magnetization of the magnetoresistive effect element 20 is likely to oscillate when a magnetic field in the Y direction is applied. When the antenna wiring 312 extends in the X direction, it is easy to apply a magnetic field in the Y direction to the magnetoresistive effect element 20.

[0044] The magnetoresistive element 20 and the antenna wiring 312 are formed, for example, inside an insulating layer 32 formed on a substrate 31. The magnetoresistive element 20 and the antenna wiring 312 are covered, for example, with the insulating layer 32.

[0045] The substrate 31 is, for example, a semiconductor substrate. The insulating layer 32 is an interlayer insulating film that insulates between wirings in a multilayer wiring structure and between elements. The insulating layer 32 is, for example, a silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride (CrN), silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO x ), magnesium oxide (MgO), aluminum nitride (AlN), etc.

[0046] The magnetoresistive element 20 has, for example, a first ferromagnetic layer 1, a second ferromagnetic layer 2, a non-magnetic layer 3, a magnetic coupling layer 4, a third ferromagnetic layer 5, and an antiferromagnetic layer 6. The magnetoresistive element 20 only needs to have at least the first ferromagnetic layer 1, the second ferromagnetic layer 2, and the non-magnetic layer 3, but may also have an underlayer, a cap layer, etc.

[0047] The first ferromagnetic layer 1 is a magnetic layer whose magnetization state changes in response to a high-frequency signal. The first ferromagnetic layer 1 is also called a magnetization free layer. The magnetization of the magnetization free layer oscillates when, for example, a high-frequency magnetic field is applied.

[0048] The first ferromagnetic layer 1 includes a ferromagnetic material. The first ferromagnetic layer 1 includes at least one of magnetic elements such as Co, Fe, or Ni. The first ferromagnetic layer 1 may include elements such as B, Mg, Hf, or Gd in addition to the magnetic elements described above. The first ferromagnetic layer 1 may be, for example, an alloy including a magnetic element and a non-magnetic element. The first ferromagnetic layer 1 may be composed of multiple layers. The first ferromagnetic layer 1 may be, for example, a CoFeB alloy, a stack of a CoFeB alloy layer sandwiched between Fe layers, or a stack of a CoFeB alloy layer sandwiched between CoFe layers. Generally, "ferromagnetic" includes "ferrimagnetic." The first ferromagnetic layer 1 may exhibit ferrimagnetic properties.

[0049] The first ferromagnetic layer 1 is preferably an in-plane magnetized film having an easy axis of magnetization in the in-plane direction (any direction within the XY plane). The easy axis of magnetization of the first ferromagnetic layer 1 is generally the long axis direction of the magnetoresistive element 20.

[0050] The film thickness of the first ferromagnetic layer 1 is, for example, 1 nm or more and 5 nm or less. The film thickness of the first ferromagnetic layer 1 is preferably, for example, 1 nm or more and 2 nm or less. When the film thickness of the first ferromagnetic layer 1 is thin, the effect of interfacial magnetic anisotropy acts strongly on the magnetization of the first ferromagnetic layer 1, and the magnetization of the first ferromagnetic layer 1 is slightly tilted from the in-plane direction toward the Z direction. When the magnetization of the first ferromagnetic layer 1 is slightly tilted from the in-plane direction toward the Z direction, the magnetization of the first ferromagnetic layer 1 is more likely to precess.

[0051] The second ferromagnetic layer 2 is a magnetization fixed layer. The magnetization fixed layer is a layer made of a magnetic material whose magnetization state is less likely to change than the magnetization free layer when a predetermined external energy is applied. For example, the magnetization direction of the magnetization fixed layer is less likely to change than the magnetization free layer when a predetermined external energy is applied. The coercive force of the second ferromagnetic layer 2 is, for example, greater than the coercive force of the first ferromagnetic layer 1. The second ferromagnetic layer 2 has an easy axis of magnetization in the same direction as the first ferromagnetic layer 1, for example. The second ferromagnetic layer 2 can be made of the same material as the first ferromagnetic layer 1.

[0052] The nonmagnetic layer 3 is sandwiched between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The nonmagnetic layer 3 includes a nonmagnetic material. When the nonmagnetic layer 3 is an insulator (a tunnel barrier layer), its material may be, for example, Al2O3, SiO2, MgO, or MgAl2O4. In addition to these, materials in which a portion of Al, Si, or Mg is substituted with Zn, Be, or the like may also be used. Among these, MgO and MgAl2O4 are materials that enable coherent tunneling, enabling efficient spin injection. When the nonmagnetic layer 3 is a metal, its material may be Cu, Au, Ag, or the like. Furthermore, when the nonmagnetic layer 3 is a semiconductor, its material may be Si, Ge, CuInSe2, CuGaSe2, Cu(In,Ga)Se2, or the like.

[0053] The magnetic coupling layer 4 is located between the second ferromagnetic layer 2 and the third ferromagnetic layer 5. The magnetic coupling layer 4 is made of, for example, Ru, Ir, or the like. The second ferromagnetic layer 2 and the third ferromagnetic layer 5 are magnetically coupled via the magnetic coupling layer 4. The magnetic coupling is, for example, antiferromagnetic coupling, and is generated by RKKY interaction.

[0054] The third ferromagnetic layer 5 is a ferromagnetic layer that is magnetically coupled to the second ferromagnetic layer 2. The magnetization of the second ferromagnetic layer 2 is strongly fixed by magnetic coupling with the magnetization of the third ferromagnetic layer 5. The third ferromagnetic layer 5 can be made of the same material as the first ferromagnetic layer 1. The third ferromagnetic layer 5 is made of, for example, Co.

[0055] The antiferromagnetic layer 6 is exchange-coupled with the third ferromagnetic layer 5. The antiferromagnetic layer 6 strongly pins the magnetization of the third ferromagnetic layer 5. The antiferromagnetic layer 6 is made of, for example, PtMn, RuMn, or IrMn.

[0056] The area resistance product (RA) of the magnetoresistive element 20 is 1 Ω·μm 2 It is preferable that the RA is equal to or less than 0.05. The RA is calculated by multiplying the resistance in the stacking direction of the magnetoresistive element 20 when the magnetization directions of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 are parallel and the area of ​​the non-magnetic layer 3 of the magnetoresistive element 20 when cut in the in-plane direction. The DC voltage generated in each magnetoresistive element 20 is output to the outside via wiring and other magnetoresistive elements 20. If the RA of the magnetoresistive element 20 is small, the loss of DC voltage to the external output can be reduced. The RA of the magnetoresistive element 20 can be reduced, for example, by reducing the thickness of the non-magnetic layer 3 or increasing the conductivity of the non-magnetic layer 3.

[0057] The spin torque diode power supply 1000 according to this embodiment can be fabricated by fabricating the power generating device 101, the output device 201, and the high frequency application device 301 and connecting them together.

[0058] The output device 201 can be fabricated by, for example, connecting a capacitor 211 and a converter 212 with wiring. The high frequency application device 301 can be fabricated by connecting an antenna 311 and an antenna wiring 312.

[0059] The power generating device 101 can be fabricated by repeatedly depositing and processing each layer. For example, sputtering, chemical vapor deposition (CVD), electron beam evaporation (EB evaporation), atomic laser deposition, etc. can be used to deposit each layer. For example, photolithography, etc. can be used to process each layer.

[0060] For example, a lower wiring 21 is formed on a substrate 31, and the periphery thereof is filled with an insulating layer 32. Next, an antiferromagnetic layer 6, a third ferromagnetic layer 5, a magnetic coupling layer 4, a second ferromagnetic layer 2, a non-magnetic layer 3, and a first ferromagnetic layer 1 are formed in this order on the lower wiring 21, and processed into a predetermined shape to produce a magnetoresistive effect element 20. The planar shape of the magnetoresistive effect elements 10, 20, and 30 can be controlled by changing the processed shape.

[0061] Next, the periphery of the magnetoresistive effect element 20 is filled with an insulating layer 32. An opening is formed at a position overlapping the lower wiring 21 in a plan view, and a conductor is filled to form a via wiring 23. Next, an upper wiring 22 is formed to connect the via wiring 23 and the magnetoresistive effect element 20. Next, an insulating layer 32 is laminated on the upper wiring 22, and an antenna wiring 312 is formed on top of that. By this procedure, the power generation device 101 can be fabricated.

[0062] The spin torque diode power supply 1000 according to this embodiment operates over a wide frequency bandwidth. This is because the power generating device 101 has multiple groups G1, G2, and G3 with different aspect ratios. The resonant frequencies of the magnetoresistive elements 10, 20, and 30 vary depending on the magnetic anisotropy of the magnetization of the first ferromagnetic layer 1. The strength of the magnetic anisotropy of the magnetization varies depending on various factors, one of which is the planar shape of the magnetoresistive elements 10, 20, and 30.

[0063] The magnetization of the first ferromagnetic layer 1 is more likely to be oriented in the long axis direction due to the influence of shape magnetic anisotropy. The larger the aspect ratio, the more likely the magnetization of the first ferromagnetic layer 1 is to be oriented in the long axis direction. In other words, the larger the aspect ratio of the first ferromagnetic layer 1, the more strongly the magnetization of the first ferromagnetic layer 1 is fixed in the long axis direction due to the influence of shape anisotropy. In other words, magnetoresistive elements with different aspect ratios have different magnitudes of shape magnetic anisotropy, resulting in differences in the ease of movement of the magnetization of the first ferromagnetic layer 1.

[0064] The resonant frequency of the magnetoresistive effect elements 10, 20, and 30 is a frequency at which the magnetization of the first ferromagnetic layer 1 easily precesses. The magnetoresistive effect elements 10, 20, and 30, which differ in the ease of movement of the magnetization of the first ferromagnetic layer 1, each have a different resonant frequency. The power generating device 101 has regions (groups G1, G2, and G3) with different resonant frequencies within its plane, and therefore operates over a wide frequency band. As a result, the spin torque diode power supply 1000 according to this embodiment can generate power even when high frequency waves in a wide frequency band are applied.

[0065] "Second embodiment" 5 is a plan view of a power generating device 102 of a spin torque diode power supply according to the second embodiment. The spin torque diode power supply according to the second embodiment differs from the spin torque diode power supply 1000 according to the first embodiment in the configuration of the power generating device 102. The other configuration of the spin torque diode power supply according to the second embodiment is the same as that of the spin torque diode power supply 1000 according to the first embodiment, and therefore a description thereof will be omitted.

[0066] The power generating device 102 has a plurality of magnetoresistance effect elements 10, 20, 30, which are divided into groups G1, G2, G3. The configurations of the magnetoresistance effect elements 10, 20, 30 and the groups G1, G2, G3 are the same as those in the first embodiment.

[0067] Groups G1, G2, and G3 of the power generation devices 102 are divided into a plurality of teams. For example, group G1 can be divided into teams t11, t12, and t13. For example, group G2 can be divided into teams t21, t22, and t23. For example, group G3 can be divided into teams t31, t32, and t33.

[0068] The teams t11, t12, and t13 are spaced apart enough to ignore the influence of the leakage magnetic field generated by the magnetoresistive elements 10 belonging to each team t11, t12, and t13. For example, the distance between the teams t11 and t12 is preferably 50 nm or more. If the distance is 50 nm or more, the effect of the significant magnetic field applied between the magnetoresistive elements 10 is reduced.

[0069] It is preferable that teams t11, t12, and t13 are aligned in the Y direction, for example. By aligning teams t11, t12, and t13 in the Y direction, the influence of the magnetic field from the nearest team in the Y direction can be suppressed. When teams t11, t12, and t13 are aligned in the X direction, they are influenced by the magnetic field from the nearest team, resulting in a large shift in the resonant frequency of the team. On the other hand, when teams t11, t12, and t13 are aligned in the X direction, the teams aligned in the X direction are more likely to resonate with each other. For example, if a resonant frequency intermediate between the resonant frequencies of teams t11 and t12 is input, teams t11 and t12 will resonate with each other, allowing for efficient power generation even at the intermediate value of their resonant frequencies.

[0070] It is preferable that all of the magnetoresistive effect elements 10 belonging to each of the teams t11, t12, and t13 are located outside the area that separates the teams t11, t12, and t13 when viewed in the Z direction. In other words, it is preferable that in each of the teams t11, t12, and t13, no magnetoresistive effect element 10 is surrounded by other magnetoresistive effect elements 10 belonging to the same team t11, t12, or t13 when viewed in a plan view from the Z direction.

[0071] For example, a magnetoresistive element 10 surrounded by other magnetoresistive elements 10 as viewed in the Z direction is defined as a central element, and one of the magnetoresistive elements surrounding the central element as viewed in the Z direction is defined as a peripheral element. The magnetic field applied to the central element is different from the magnetic field applied to the peripheral element. This is because the central element receives a leakage magnetic field from the magnetoresistive elements surrounding the central element. For example, when the ferromagnetic layer of the peripheral element oscillates, the ferromagnetic layer of the central element may not oscillate in response to that oscillation.

[0072] In contrast, if there is no element that corresponds to the center element, the difference in the magnitude of the magnetic field applied to each magnetoresistance effect element 10 becomes small. Therefore, if the ferromagnetic layer of one magnetoresistance effect element 10 oscillates, the ferromagnetic layers of the other magnetoresistance effect elements 10 also tend to oscillate in response to that oscillation. In other words, team t11, t12, and t13 resonate as a whole, and the team t11, t12, and t13 can generate a large output as a whole.

[0073] In each of the teams t11, t12, and t13, it is preferable that the number of magnetoresistive effect elements 10 aligned in the X direction be greater than the number of magnetoresistive effect elements 10 aligned in the Y direction. For example, in the example of Fig. 5, team t11 has three elements aligned in the X direction and two elements aligned in the Y direction, which satisfies this requirement.

[0074] The leakage magnetic field from the magnetoresistive element 10 tends to occur in the X direction. This is because the magnetization of each ferromagnetic layer of the magnetoresistive element 10 is oriented in the long axis direction of the magnetoresistive element 10, and magnetic flux lines tend to occur in the X direction. In other words, the ferromagnetic layers of the magnetoresistive elements 10 aligned in the X direction tend to resonate with each other. When there are a large number of magnetoresistive elements 10 aligned in the X direction, the team t11, t12, and t13 tend to resonate as a whole, and the team t11, t12, and t13 tend to produce a large output as a whole.

[0075] Teams t21, t22, t23 and teams t31, t32, t33 are similar to teams t11, t12, t13. The team arrangements and the arrangements of the magnetoresistive effect elements in teams t21, t22, t23 and teams t31, t32, t33 are preferably similar to teams t11, t12, t13.

[0076] "Third embodiment" 6 is a plan view of a power generating device 103 of a spin torque diode power supply according to the third embodiment. The spin torque diode power supply according to the third embodiment differs from the spin torque diode power supply 1000 according to the first embodiment in the configuration of the power generating device 103. The other configuration of the spin torque diode power supply according to the third embodiment is the same as that of the spin torque diode power supply 1000 according to the first embodiment, and therefore a description thereof will be omitted.

[0077] The power generating device 103 has a plurality of magnetoresistance effect elements 10, 20, and 30, which are divided into groups G1, G2, and G3. The configurations of the magnetoresistance effect elements 10, 20, and 30 and the groups G1, G2, and G3 are the same as those in the first embodiment.

[0078] A magnetic shield 40 is formed between the groups G1, G2, and G3 of the power generation device 102. A known magnetic shield can be used as the magnetic shield 40. For example, the magnetic shield may be a soft magnetic material such as a NiFe alloy or ferrite.

[0079] The magnetic shield 40 reduces the leakage magnetic field between the groups G1, G2, and G3. When a leakage magnetic field from another group is applied to a group that is resonating at a specific frequency, the resonance is disrupted. As a result, the output from the group that was resonating at the specific frequency may become smaller. By using the magnetic shield 40 to reduce the leakage magnetic field between the groups G1, G2, and G3, the risk of a leakage magnetic field from another group disrupting the resonance of a specific group can be reduced.

[0080] Although an example in which the magnetic shield 40 is placed between the groups G1, G2, and G3 has been shown here, the magnetic shield 40 may be placed in other locations. For example, the magnetic shield 40 may be placed so as to surround the periphery of the power generation device, or may be placed above and below the power generation device, or the magnetic shield 40 may be placed between the teams shown in the second embodiment.

[0081] "Fourth embodiment" 7 is a plan view of a power generating device 104 of a spin torque diode power supply according to the fourth embodiment. The spin torque diode power supply according to the fourth embodiment differs from the spin torque diode power supply 1000 according to the first embodiment in the configuration of the power generating device 104. The other configurations of the spin torque diode power supply according to the fourth embodiment are the same as those of the spin torque diode power supply 1000 according to the first embodiment, and therefore a description thereof will be omitted.

[0082] The power generating device 104 has a plurality of magnetoresistance effect elements 10, 20, and 30, which are divided into groups G1, G2, and G3. The configurations of the magnetoresistance effect elements 10, 20, and 30 are the same as those in the first embodiment.

[0083] In the power generation device 104, the multiple groups G1, G2, and G3 are aligned, for example, in the Y direction. By aligning them in the Y direction, the magnetic fields generated by the multiple magnetoresistance effect elements belonging to each group are less likely to affect other groups, making it possible to transmit signals stably.

[0084] In the first to third embodiments, an example was shown in which the groups G1, G2, and G3 were arranged in the X direction, and in the fourth embodiment, an example was shown in which the groups G1, G2, and G3 were arranged in the Y direction, but the arrangement of the groups G1, G2, and G3 is not limited to this example. For example, the groups may be arranged in the X and Y directions, or the groups may be arranged randomly.

[0085] The specific configurations of the spin torque diode power supply have been described above by illustrating the first to fourth embodiments. The spin torque diode power supply according to the present disclosure is not limited to these exemplary configurations, and various modifications are possible within the scope of the gist of the present disclosure. [Explanation of symbols]

[0086] 1 First ferromagnetic layer 2 Second ferromagnetic layer 3 Non-magnetic layer 4 Magnetic coupling layer 5 Third ferromagnetic layer 6 Antiferromagnetic layer 10, 20, 30 Magnetoresistive element 21 Lower wiring 22 Upper wiring 23 Via wiring 31 PCB 32 Insulating layer 40 Magnetic Shield 101, 102, 103, 104 Power generating equipment 111 1st terminal 112 2nd terminal 201 Output Device 211 Capacitor 212 Converter 301 High frequency application device 311 Antenna 312 Antenna wiring 1000 Spin Torque Diode Power Supply G1, G2, and G3 groups t11, t12, t13, t21, t22, t23, t31, t32, t33 teams

Claims

1. It has multiple groups, each of the plurality of groups includes a plurality of magnetoresistive effect elements connected to satisfy at least one of a series and a parallel relationship; Magnetoresistive elements belonging to the same group have a constant aspect ratio between the long axis length and the short axis length when viewed in a plan view from the stacking direction, The magnetoresistive elements belonging to different groups have different aspect ratios of their major axis lengths and minor axis lengths when viewed in a plan view from the stacking direction, The spin torque diode power supply, wherein the minor axis length of the magnetoresistive effect elements belonging to the group having the aspect ratio closest to 1 is longer than the minor axis length of the magnetoresistive effect elements belonging to other groups.

2. Further comprising a first terminal and a second terminal, The spin torque diode power supply of claim 1 , wherein the plurality of groups are connected in series or in parallel between the first terminal and the second terminal.

3. Each of the plurality of magnetoresistive elements has a resistance-area product (RA) of 1 Ω·μm ２ 2. A spin torque diode power supply as claimed in claim 1, wherein:

4. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, 2. The spin torque diode power supply according to claim 1, wherein in each of the plurality of groups, the magnetoresistive elements aligned in the second direction are connected in series.

5. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, The spin torque diode power supply of claim 1 , wherein the groups are aligned in the first direction.

6. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, The spin torque diode power supply of claim 1 , wherein the groups are aligned in the second direction.

7. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, any one of the plurality of groups includes a plurality of teams each including a plurality of magnetoresistive effect elements; 2. The spin torque diode power supply according to claim 1, wherein in each of the plurality of teams, the number of magnetoresistive effect elements aligned in the first direction is greater than the number of magnetoresistive effect elements aligned in the second direction.

8. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, any one of the plurality of groups includes a plurality of teams each including a plurality of magnetoresistive effect elements; The spin torque diode power supply of claim 1 , wherein the plurality of teams are aligned in the group in a second direction.

9. any one of the plurality of groups includes a plurality of teams each including a plurality of magnetoresistive effect elements; 2. The spin torque diode power supply of claim 1, wherein the magnetoresistive effect elements belonging to each of the plurality of teams are not surrounded by other magnetoresistive effect elements belonging to the same team when viewed in a plane from the stacking direction.

10. Having a plurality of groups, each of the plurality of groups includes a plurality of magnetoresistive effect elements connected to satisfy at least one of a series and a parallel relationship; Magnetoresistive elements belonging to the same group have a constant aspect ratio between the long axis length and the short axis length when viewed in a plan view from the stacking direction, The magnetoresistive elements belonging to different groups have different aspect ratios of their major axis lengths and minor axis lengths when viewed in a plan view from the stacking direction, Further provided with a magnetic shield, The magnetic shield is disposed between the plurality of groups.

11. Having a plurality of groups, each of the plurality of groups includes a plurality of magnetoresistive effect elements connected to satisfy at least one of a series and a parallel relationship; Magnetoresistive elements belonging to the same group have a constant aspect ratio between the long axis length and the short axis length when viewed in a plan view from the stacking direction, The magnetoresistive elements belonging to different groups have different aspect ratios of their major axis lengths and minor axis lengths when viewed in a plan view from the stacking direction, Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, In each of the plurality of groups, the distance between the magnetoresistive effect elements adjacent to each other in the first direction is smaller than the distance between the magnetoresistive effect elements adjacent to each other in the second direction.

12. further comprising an antenna and an antenna wiring; 2. The spin torque diode power supply according to claim 1, wherein the antenna wiring is configured so that a magnetic field generated from the antenna wiring can be applied to at least one of the plurality of magnetoresistive effect elements.

13. Each of the plurality of magnetoresistive elements has a major axis oriented in a first direction and a minor axis oriented in a second direction perpendicular to the first direction, The spin torque diode power supply according to claim 12 , wherein the antenna wiring is positioned along the magnetoresistive elements aligned in the first direction.

14. further comprising an output device; 3. The spin torque diode power supply of claim 2, wherein the output device is connected to the first terminal and the second terminal.

15. the impedance between the first terminal and the second terminal is 50Ω±25Ω; 15. The spin torque diode power supply of claim 14, wherein the output device impedance is 50 ohms ± 25 ohms.

Images