Orbital electronic memory device based on orbital torque effect

Abstract

The application provides an orbital electronic memory device based on an orbital torque effect. The orbital torque heterojunction, the orbital torque magnetic tunnel junction device and the orbital Hall nanometer oscillator device are prepared by a magnetron sputtering method, a weak spin-orbital coupling effect material is used as a non-magnetic layer to replace a heavy metal or a topological insulator, and the weak spin-orbital coupling effect material includes light metals Al, Ti, V, Cr, Mn, Cu and oxide and nitride films thereof, and the orbital Hall effect based on the weak spin-orbital coupling effect material is used to realize the flip or precession of a magnetic moment. The orbital electronic memory device based on the orbital torque effect has many advantages such as low cost, high stability, simple process and being conducive to industrialization.

Description

Technical Field

[0001] This invention relates to the field of electronic memory, and more specifically, to a track electronic memory device based on the track torque effect. Background Technology

[0002] Spin-orbit moment electronic storage logic devices have attracted widespread attention due to their ability to achieve low power consumption, high speed, and high density data storage.

[0003] Spin-orbit moment electronic storage logic devices can achieve the conversion of charge flow to spin flow by constructing ferromagnetic / nonmagnetic heterojunctions and utilizing the spin Hall effect of the nonmagnetic layer. Spin flow has the significant advantage of no Joule heat dissipation compared to charge flow.

[0004] The spin current entering the ferromagnetic layer generates a spin-orbit torque, resulting in a reversal of the magnetic moment. However, the spin Hall effect depends on strong spin-orbit coupling, and can only be achieved in heavy metals (Au, Pt, Ta, W, Pd) or topological insulators (BiSe, BiTe) with strong spin-orbit coupling. However, the use of heavy metals and topological insulators leads to high costs or difficulties in fabrication techniques.

[0005] The orbital Hall effect does not depend on strong spin-orbit coupling effects [e.g., Reference 1: GoD, Jo D, Kim C, et al. Intrinsic spin and orbital Hall effects from orbital texture: Physical Review Letters, 10.1103 / PhysRevLett.121.086602[P].2018.; Reference 2: Jo D, Go D, Lee H W. Gigantic intrinsic orbital Hall effects in weakly spin-orbit coupled metals: Physical Review B, 10.1103 / PhysRevB.98.214405[P].2018.], and can be achieved in light metals and their oxides, nitrides, and other materials with weak spin-orbit coupling effects.

[0006] Combining materials with weak spin-orbit coupling effects with ferromagnetic materials to form heterojunctions can achieve a similar conversion between charge flow and orbital flow, similar to the spin Hall effect. The orbital flow then enters the ferromagnetic layer, achieving a conversion between orbital flow and spin flow, generating orbital torque that flips the magnetic moment of the ferromagnetic layer, thus realizing the conversion between charge flow, orbital flow, and spin flow. This can then enable memory devices based on orbital torque, effectively solving the problems of high cost and difficult fabrication technology mentioned above. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing a spintronic storage device based on orbital torque, which enables low-cost, low-power, high-speed, and high-density data storage.

[0008] Spintronic memory devices based on orbital torque combine ferromagnetic materials with nonmagnetic materials with weak spin-orbit coupling effects to form ferromagnetic / nonmagnetic heterojunctions. The weak spin-orbit coupling effect material acts as an orbital Hall effect channel to generate orbital flow, which enters the ferromagnetic material to generate orbital torque and achieve magnetic moment reversal.

[0009] The spintronic memory device based on orbital torque consists of, from bottom to top, a single-crystal substrate, a non-magnetic layer, a ferromagnetic layer, and a protective layer. The orbital torque heterojunction device is fabricated using micro-nano fabrication. The thickness of the non-magnetic layer is 4-100 nm.

[0010] The spintronic memory device based on orbital torque consists of, from bottom to top: a single-crystal substrate, a non-magnetic layer, a ferromagnetic free layer, an insulating barrier layer, a ferromagnetic pinning layer, and a protective layer. The orbital torque magnetic tunnel junction device is fabricated using micro-nano fabrication. The thickness of the non-magnetic layer is 4-100 nm.

[0011] Furthermore, the non-magnetic layer may be any one or more of Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides.

[0012] Furthermore, the ferromagnetic layer may be any one or more of Co, Fe, Ni, NiFe, and CoFeB.

[0013] Furthermore, the protective layer is made of MgO.

[0014] Furthermore, the ferromagnetic free layer and the ferromagnetic pinning layer are made of CoFeB.

[0015] Furthermore, the insulating barrier layer is made of MgO.

[0016] Furthermore, during fabrication, a non-magnetic layer, a ferromagnetic layer, and a protective layer are sequentially deposited on a single-crystal substrate using a magnetron sputtering method.

[0017] Among them, Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides are selected as one or more of the target materials for weak spin-orbit coupling effect, that is, as non-magnetic layers;

[0018] Choose any one or more of Co, Fe, Ni, NiFe, and CoFeB as the ferromagnetic target material, that is, as the ferromagnetic layer;

[0019] During preparation, an Ar atmosphere was used for sputtering at a pressure of 2.5-3.0 mTorr;

[0020] The DC sputtering power for ferromagnetic and non-magnetic layers is 30-50W.

[0021] The MgO RF sputtering power is 150W.

[0022] Furthermore, during the fabrication process, a non-magnetic layer, a ferromagnetic free layer, an insulating barrier layer, a ferromagnetic pinning layer, and a protective layer are sequentially deposited on the single-crystal substrate using a magnetron sputtering method.

[0023] During preparation, an Ar atmosphere was used for sputtering at a pressure of 2.5-3.0 mTorr;

[0024] The DC sputtering power for the ferromagnetic free layer, insulating barrier layer, and ferromagnetic pinning layer is 30-50W.

[0025] The sputtering power of the protective layer is 150W.

[0026] The technical solution of this invention is:

[0027] The beneficial effects of this application are as follows:

[0028] First, orbital electronic storage devices based on the orbital torque effect can generate orbital torque by replacing materials with materials with strong and weak spin-orbit coupling effects with materials with weak spin-orbit coupling effects, thereby achieving magnetic moment reversal or precession. This enables low-cost, high-speed, high-density, and low-power information storage.

[0029] Second, the samples can be prepared by magnetron sputtering, which has the advantages of simple preparation method, industrialization, and low cost, in line with the concept of sustainable development. In particular, this application provides key process parameters: the sputtering atmosphere is Ar atmosphere with a pressure of 2.5-3.0 mTorr; the DC sputtering power of the ferromagnetic free layer, insulating barrier layer, and ferromagnetic pinned layer is 30-50W; and the frequency sputtering power of the protective layer is 150W.

[0030] Third, the third inventive point of this application is that the thickness of the non-magnetic layer is 4-100 nm. The applicant's current experiments show that the orbital Hall effect can occur when the thickness of the non-magnetic layer is 4-100 nm. Attached Figure Description

[0031] The present invention will be further described in detail below with reference to the embodiments shown in the accompanying drawings, but this does not constitute any limitation on the present invention.

[0032] Figure 1 This is a schematic diagram of the orbital Hall effect.

[0033] Figure 2 This is a structural design diagram of a track torque heterojunction device.

[0034] Figure 3 A physical image of a track torque heterojunction device.

[0035] Figure 4 This is a structural design diagram of a track torque magnetic tunnel junction device.

[0036] Figure 5 This is a structural design diagram of the Dao Hall nano-oscillator device. Detailed Implementation

[0037] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the materials used in the following embodiments are conventional materials; and the experimental methods described are conventional methods.

[0038] The present invention will now be described in detail with reference to the accompanying drawings, providing a complete description of the technical solution of the present invention.

[0039] Example 1: Hardware design and fabrication method of track torque heterojunction device

[0040] like Figure 1 As shown, a schematic diagram of the orbital Hall effect is presented, in which charge flow is converted into orbital flow in materials with weak spin-orbit coupling effect.

[0041] like Figure 2 and 3 As shown, the structural design diagram and measurement diagram of the orbital torque heterojunction device are presented. The ferromagnetic / nonmagnetic heterojunction is constructed by combining ferromagnetic materials with nonmagnetic materials with weak spin-orbit coupling effect. The weak spin-orbit coupling effect material serves as the orbital flow generated by the orbital Hall effect channel, which enters the ferromagnetic material to generate orbital torque and realize the reversal of magnetic moment.

[0042] The hardware design concept of the track torque heterojunction device is:

[0043] 1) By utilizing materials with weak spin-orbit coupling effects as orbital Hall effect channels, charge flow is converted into orbital flow, which enters ferromagnetic materials to generate orbital moments, thereby achieving magnetic moment reversal and realizing electronic storage devices based on orbital moments. This effectively avoids Joule heat dissipation and avoids dependence on precious metals.

[0044] 2) The following layers are arranged from bottom to top: single crystal substrate, non-magnetic layer (light metals Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides), ferromagnetic layer (Co, Fe, Ni, NiFe, CoFeB, etc.), and protective layer (MgO, etc.), and then the orbital torque heterojunction device is fabricated through micro-nano processing.

[0045] The fabrication method of the track torque heterojunction device is as follows:

[0046] Using magnetron sputtering, a non-magnetic layer, a ferromagnetic layer, and a protective layer are sequentially deposited on a single-crystal substrate. Ferromagnetic targets such as Co, Fe, Ni, NiFe, and CoFeB, and targets made of light metals such as Al, Ti, V, Cr, Mn, and Cu with weak spin-orbit coupling effects are selected. Necessary process parameters are adjusted to achieve film formation, with the thickness of the light metal layer ranging from 4 to 100 nm.

[0047] The reaction parameters include: substrate temperature (room temperature), sputtering atmosphere (Ar atmosphere, pressure 2.5-3.0 mTorr), DC sputtering power of ferromagnetic and non-magnetic layers (30-50W), and RF sputtering power of MgO (150W).

[0048] Ferromagnetic layers include Co, Fe, Ni, NiFe, CoFeB thin films, etc., while non-magnetic layers include light metals such as Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides.

[0049] Example 2: Track Torque Magnetic Tunnel Junction Device and Its Fabrication Method

[0050] like Figure 4 As shown, a structural design diagram of a magnetic tunnel junction device with orbital torque is presented. A weak spin-orbit coupling effect material is used as the orbital Hall effect channel, and a sandwich structure of ferromagnetic layer / barrier layer / ferromagnetic layer is fabricated on it. Based on the orbital Hall effect of the weak spin-orbit coupling effect material, an orbital flow is generated, which enters the ferromagnetic free layer to generate an orbital torque and realize the reversal of the magnetic moment.

[0051] The nonmagnetic layer of the orbital Hall effect channel includes light metals such as Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides, while the ferromagnetic layer includes CoFeB thin films, CoFeB / Gd / CoFeB three-layer films, etc., and the barrier layer is a MgO thin film.

[0052] The hardware design concept of the track torque magnetic tunnel junction device is to use a material with weak spin-track coupling effect as a track Hall effect channel to convert charge flow into track flow, which enters the ferromagnetic free layer in the magnetic tunnel junction sandwich structure to generate track torque and realize the reversal of magnetic moment, thereby realizing the tunnel magnetoresistance effect controlled by track flow, and achieving low-cost, high-density, high-speed, and low-power information storage.

[0053] The fabrication method of the track torque magnetic tunnel junction device is as follows:

[0054] The orbital torque magnetic tunnel junction device is fabricated using magnetron sputtering, and from bottom to top, consists of: a single-crystal substrate / non-magnetic layer (light metals Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides) / ferromagnetic free layer (CoFeB or CoFeB / Gd / CoFeB, etc.) / insulating barrier layer (MgO) / ferromagnetic pinning layer (CoFeB or CoFeB / Gd / CoFeB) / protective layer (MgO, etc.). The orbital torque magnetic tunnel junction device is then fabricated using micro / nano fabrication.

[0055] Using magnetron sputtering, targets such as CoFeB ferromagnetic materials and Gd, as well as targets with weak spin-orbit coupling effects such as light metals Al, Ti, V, Cr, Mn, and Cu, were selected, and necessary process parameters were adjusted to achieve film formation. Reaction parameters included: substrate temperature (room temperature), sputtering atmosphere (Ar atmosphere, pressure 2.5-3.0 mTorr), DC sputtering power for ferromagnetic and non-magnetic layers (30-50 W), and RF sputtering power for MgO (150 W), etc. The thickness of the light metal layer was 4-100 nm.

[0056] Example 3: Orbital Hall Nano-Oscillator Device and Its Fabrication Method

[0057] like Figure 5 The diagram shows the structural design of the orbital Hall nano-oscillator device. A ferromagnetic / non-magnetic heterojunction is constructed by combining ferromagnetic materials with a weak spin-orbit coupling effect non-magnetic material. The weak spin-orbit coupling effect material acts as a channel for the orbital Hall effect, generating orbital currents that enter the ferromagnetic material, thus generating orbital moments and achieving high-frequency precession of the magnetic moment. The ferromagnetic layer includes NiFe and CoFeB thin films, while the non-magnetic layer includes light metals such as Al, Ti, V, Cr, Mn, Cu, and their oxides and nitrides.

[0058] The hardware design concept of the orbital Hall nano-oscillator device is to utilize a material with a weak spin-orbit coupling effect as an orbital Hall effect channel to convert charge flow into orbital flow, which enters the ferromagnetic material to generate orbital moment, thereby achieving high-frequency precession of magnetic moment and realizing an electronic device based on orbital moment. This effectively avoids Joule heat dissipation and avoids dependence on precious metals.

[0059] The fabrication method of the orbital Hall nano-oscillator device is as follows: from bottom to top, the following layers are set: single crystal substrate / non-magnetic layer (light metals Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides) / ferromagnetic layer (Co, Fe, Ni, NiFe, CoFeB, etc.) / protective layer (MgO, etc.), and then the orbital Hall nano-oscillator device is fabricated through micro-nano processing.

[0060] Using magnetron sputtering, NiFe and CoFeB ferromagnetic targets and light metal targets with weak spin-orbit coupling effects such as Al, Ti, V, Cr, Mn, and Cu were selected, and necessary process parameters were adjusted to achieve film formation. Reaction parameters included: substrate temperature (room temperature), sputtering atmosphere (Ar atmosphere, pressure 2.5-3.0 mTorr), DC sputtering power for ferromagnetic and non-magnetic layers (30-50 W), and RF sputtering power for MgO (150 W), etc. The thickness of the light metal layer was 4-100 nm.

[0061] The above-described embodiments are preferred embodiments of the present invention and are only used to facilitate the illustration of the present invention. They are not intended to limit the present invention in any way. Any person skilled in the art who makes local modifications or alterations to the technical content disclosed in the present invention without departing from the scope of the technical features of the present invention shall still fall within the scope of the technical features of the present invention.

Claims

1. A spintronic storage device based on orbital torque, characterized in that, Ferromagnetic materials are combined with nonmagnetic materials with weak spin-orbit coupling effect to form ferromagnetic / nonmagnetic heterostructures. The weak spin-orbit coupling effect material acts as an orbital flow generated by the orbital Hall effect channel, which enters the ferromagnetic material to generate orbital moment and realize the reversal of magnetic moment. The following layers are arranged from bottom to top: single crystal substrate, non-magnetic layer, ferromagnetic layer, and protective layer. Orbit torque heterojunction devices and orbit Hall nano-oscillator devices are fabricated through micro-nano processing. The non-magnetic layer is made of any one or more of Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides, and its thickness is 4-100 nm. The ferromagnetic layer is made of any one or more of Co, Fe, Ni, NiFe, and CoFeB. The protective layer is made of MgO; During fabrication, a non-magnetic layer, a ferromagnetic layer, and a protective layer were sequentially deposited on a single-crystal substrate using magnetron sputtering. During fabrication, an Ar atmosphere was used for sputtering at a pressure of 2.5-3.0 mTorr. The DC sputtering power for the ferromagnetic and non-magnetic layers was 30-50 W, and the RF sputtering power for MgO was 150 W.

2. A spintronic storage device based on orbital torque, characterized in that, Ferromagnetic materials are combined with nonmagnetic materials with weak spin-orbit coupling effect to form ferromagnetic / nonmagnetic heterostructures. The weak spin-orbit coupling effect material acts as an orbital flow generated by the orbital Hall effect channel, which enters the ferromagnetic material to generate orbital moment and realize the reversal of magnetic moment. From bottom to top, the layers are: single crystal substrate, non-magnetic layer, ferromagnetic free layer, insulating barrier layer, ferromagnetic pinning layer, and protective layer. Orbit torque magnetic tunnel junction devices are fabricated through micro-nano fabrication. The non-magnetic layer is made of any one or more of Al, Ti, V, Cr, Mn, Cu and their oxides and nitrides, and its thickness is 4-100 nm. The protective layer is made of MgO; Among them, the ferromagnetic free layer and the ferromagnetic pinning layer are made of CoFeB; The insulating barrier layer is made of MgO; During fabrication, a non-magnetic layer, a ferromagnetic free layer, an insulating barrier layer, a ferromagnetic pinning layer, and a protective layer were sequentially deposited on a single-crystal substrate using magnetron sputtering. During fabrication, an Ar atmosphere was used for sputtering at a pressure of 2.5-3.0 mTorr. The DC sputtering power for the ferromagnetic free layer, the insulating barrier layer, and the ferromagnetic pinning layer was 30-50 W, while the frequency sputtering power for the protective layer was 150 W.

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