47 results about "Exchange bias" patented technology

The invention provides a magnetic memory and an array thereof, relates to the technical field of semiconductors, and is used for improving a writing mode of the magnetic memory and realizing a high-density magnetic memory array. According to the magnetic memory structure provided by the invention, the bias region is arranged, and the interior of the bias region is at least filled with the ferromagnetic layer, the antiferromagnetic layer and the seed layer, so that the stability of the magnetic memory can be effectively improved; the stray field generated by the ferromagnetic layer can assist the magnetic direction of the free layer in flipping, so that field-free flipping is realized, the polarity of the ferromagnetic layer can still be stable after the magnetic memory is miniaturized due to the exchange bias effect generated between the ferromagnetic layer and the anti-ferromagnetic layer, the device stability after the size of the magnetic memory is miniaturized is further improved, and the reliability of the magnetic memory is improved. And realization of a high-density magnetic memory array is facilitated.

The invention discloses a vertical exchange bias structure and a preparation method thereof, and belongs to the technical field of information technology and spintronics, the preparation method of the vertical exchange bias structure comprises the following steps: fixing a substrate on a substrate table of a vacuum sputtering chamber, adjusting the vacuum degree, and sputtering a buffer layer on the upper surface of the substrate; sequentially sputtering a seed layer, a magnetic layer, an interface magnetic layer, an antiferromagnetic layer and a protective layer on the upper surface of the buffer layer to obtain the vertical exchange bias structure; the interface magnetic layer is Pt / CoFe, the period is 1, the sputtering power of the CoFe layer is 10W, and the sputtering air pressure is 0.7 Pa. According to the method, the exchange bias effect of the magnetic film is regulated and controlled by changing the characteristics and growth conditions of the interface magnetic layer, the overall magnetism of the magnetic layer is kept unchanged, and the method has important guiding significance for designing the structures of magnetic materials and devices.

A magnetoresistive element for a magnetic sensor, the magnetoresistive element including a tunnel barrier layer between a reference layer having a fixed reference magnetization and a sense layer having a free sense magnetization, wherein the sense magnetization includes a stable vortex configuration. The magnetoresistive element further includes a reference pinning layer in contact with the reference layer and pining the reference magnetization by exchange-bias at a first blocking temperature. The magnetoresistive element further includes a sense pinning layer in contact with the sense layer and pining the sense magnetization by exchange-bias at a second blocking temperature lower that the first blocking temperature. Additionally, a method for manufacturing the magnetoresistive element.

The invention discloses a multi-layer thin film structure capable of achieving vertical exchange bias and free of external field auxiliary total current overturning and a preparation method and application thereof, the multi-layer thin film structure sequentially comprises a heavy metal base layer, an atomic level intercalation layer, a ferromagnetic layer and an antiferromagnetic layer from bottom to top, and the multi-layer thin film structure is prepared through molecular beam epitaxy. According to the invention, anisotropic epitaxial strain is introduced into the antiferromagnetic layer, so that a remarkable vertical exchange bias effect at room temperature is realized. Meanwhile, a global uncompensated magnetic moment is generated in the anisotropic epitaxial strain induction antiferromagnetic layer, an energy barrier of vertical exchange bias flipping is reduced, current-driven exchange bias flipping without an external field is further realized through a spin-orbit moment effect, the dependence on an external magnetic field in the prior art is overcome, and the performance of the device is improved. And the integration and the application potential of the spinning electronic device are obviously improved. The technology lays a foundation for design and development of efficient and high-density magnetic storage and logic devices.

The invention aims to design a composite material capable of improving a magnetic exchange bias field. The material is a porous nano alpha-Fe2O3 / g-C3N4 composite material capable of improving the magnetic exchange bias field, which is synthesized by loading g-C3N4 on an ordered alpha-Fe2O3 nanowire. The method is simple to operate, environment-friendly and low in energy consumption; the porous nano composite material prepared by the method has a relatively high specific surface area, and meanwhile, the composite material has more surface disordered spinning, so that the blocking temperature and coercive force of the composite material are improved, the exchange bias field of the composite material is improved, and the composite material has a relatively good practical utilization prospect.

A device with adjustable exchange bias based on a low-dimensional antiferromagnetic / ferromagnetic insulator heterojunction. A device with adjustable exchange bias based on a low-dimensional antiferromagnetic / ferromagnetic insulator heterojunction. (1) A heterojunction is formed by covering an antiferromagnetic topological insulator with a low-dimensional ferromagnetic insulator; there are two configurations of the heterojunction, namely, the ferromagnetic insulator completely covering the antiferromagnetic topological insulator and the ferromagnetic insulator semi-covering the antiferromagnetic topological insulator; (2) A non-magnetic insulating protective layer is covered above the heterojunction; (3) In the heterojunction, an obvious exchange bias effect can be observed; (4) By changing the coverage range of the ferromagnetic insulator, the sign of the exchange bias can be regulated; (5) The material system used for the device is van der Waals layered materials; by changing the coverage range of the ferromagnetic insulator, the sign of the exchange bias can be regulated; below the Curie temperature and Néel temperature of the magnetic material, the anomalous Hall effect can be measured by using low temperature and magnetic field for magnetotransport measurement.

The application discloses a magnetoelectric heterojunction film and a preparation method thereof. The magnetoelectric heterojunction film comprises a strontium titanate base layer, a strontium ruthenate electrode layer, a bismuth ferrite ferroelectric material layer and a SmCo-based ferromagnetic material layer which are stacked in sequence. The magnetoelectric heterojunction film has the multi-ferroelectric layer room-temperature magnetoelectric coupling effect and the excellent magnetic performance of the ferromagnetic layer, and the magnetoelectric coupling effect of the heterojunction film can be enhanced through the strong exchange bias effect at the interface.

The invention relates to the technical field of magnetic materials, in particular to MOF precursor-based magnetic powder and a preparation method and application thereof.The preparation method comprises the following steps: mixing an iron source, a platinum source, an organic ligand and a solvent to obtain a mixture; performing heat treatment on the mixture to obtain a precursor MOF material; washing, centrifuging and drying the precursor MOF material, grinding and sieving to obtain precursor nanoparticles; and calcining the precursor nano-particles to obtain the magnetic powder. The magnetic powder is synthesized through the hydrothermal method, the high-temperature calcination method is combined, preparation of the magnetic powder with high exchange bias is achieved, and the preparation method has the technical effects of simplifying the process and improving the performance; in addition, the magnetic powder prepared by the preparation method has a strong exchange bias field at low temperature under a magnetic condition at room temperature.

A method to calculate performance of a magnetic element including a reference bilayer including a ferromagnetic reference layer having a reference magnetization and an antiferromagnetic layer pining the reference magnetization by exchange-bias, the antiferromagnetic layer including a metallic polycrystalline material having a grain volume distribution; the method including: measuring an exchange-bias field (Hex) of the antiferromagnetic layer as a function of temperature; fitting a grain volume distribution function to the measured exchange-bias fields (Hex) to determine parameters characterizing the volume distribution function; calculating a variation in the direction of the reference magnetization as a function of a direction of an exposure magnetic field (H); and calculating the exchange bias field (Hex) for any value of the in-plane exposure field (H).

The application discloses a multi-state memory unit based on anti-ferromagnetic, and relates to the technical field of spintronic devices, and aims to solve the problems that multi-bit storage of a single device cannot be realized and data writing is difficult in the prior art.The application comprises a magnetic tunnel junction, a bottom electrode layer serving as a current writing line, the magnetic tunnel junction is used for storing data, and the bottom electrode layer is used for providing spin-orbit torque to write data; the magnetic tunnel junction at least comprises a fixed layer, a barrier layer and a free layer; the free layer is adjacent to an anti-ferromagnetic layer, and exchange bias is formed between the anti-ferromagnetic layer and the free layer; a current is applied on the corresponding bottom electrode to reverse the direction of the free layer and the exchange bias to a direction perpendicular to the current; and the free layer and the exchange bias are controlled to reverse the angle by applying the current in the current writing line at different angles, so that more intermediate states can be obtained in the whole magnetic resistance range. Not only can the application realize magnetic field-free writing of data, but also can realize extremely stable multi-bit storage.

The invention discloses a flexible thin film structure with a vertical exchange bias effect and a preparation method and application thereof, and belongs to the technical field of spinning electron and flexible integration. A flexible thin film structure with a vertical exchange bias effect comprises a polyimide flexible substrate, a wedge-shaped buffer layer, a wedge-shaped seed layer, a ferromagnetic layer, an antiferromagnetic layer and a protective layer from bottom to top in sequence. Wherein the polyimide flexible substrate, the ferromagnetic layer, the antiferromagnetic layer and the protective layer are all flat structure layers. The wedge-shaped buffer layer and the wedge-shaped seed layer are adopted between the polyimide flexible substrate and the magnetic layer at the same time, the thickness of the polyimide flexible substrate is set to be 10-15 microns, the stress performance of the thin film is improved by adopting the structure, the thin film can be completely compatible with a CMOS (Complementary Metal Oxide Semiconductor) processing technology of a device, and the performance of the thin film is improved. Miniaturization and batch production of the flexible device can be realized, and the complexity of the preparation process of the flexible electronic device in the wearable device is obviously reduced.

The linear sensor comprises a ferromagnetic layer, an antiferromagnetic layer and a heavy metal layer, the ferromagnetic layer is arranged on the upper surface of the antiferromagnetic layer, and the heavy metal layer is arranged on the upper surface of the ferromagnetic layer as a protective layer; during working, a Wheatstone bridge structure is adopted, the included angle between the magnetization pinning direction on each bridge arm and the long axis direction is 45 degrees, and the magnetic resistance response trends of the magnetic resistance on the adjacent bridge arms to the same external magnetic field are opposite; one-way current pulses with set amplitudes are introduced into the two ends of the magnetic resistor to complete the induction of exchange bias. According to the invention, through the selection of each layer of material of the sensor film, the design of the growth sequence and the design of the rear-end Wheatstone bridge, the regulation and control of the Wheatstone full-bridge structure sensor can be realized in a non-magnetic environment only through one-time current pulse. The growth efficiency of the magnetic sensor is greatly improved, the regulation and control steps are reduced, and the regulation and control procedure of the sensor is simplified.

The present invention discloses a multi-layer thin film structure for realizing vertical exchange bias and all-current switching without external field assistance, and its preparation method and application. The multi-layer thin film structure sequentially includes a heavy metal underlayer, an atomic-level interlayer, a ferromagnetic layer, and an antiferromagnetic layer from bottom to top, and the multi-layer thin film structure is prepared by molecular beam epitaxy. The present invention realizes a significant vertical exchange bias effect at room temperature by introducing anisotropic epitaxial strain in the antiferromagnetic layer. At the same time, the anisotropic epitaxial strain induces a global uncompensated magnetic moment in the antiferromagnetic layer, reduces the energy barrier for vertical exchange bias switching, and further realizes current-driven exchange bias switching without an external field through the spin-orbit torque effect, overcoming the dependence on an external magnetic field in the prior art and significantly improving the integrability and application potential of spintronic devices. This technology lays a foundation for the design and development of high-efficiency and high-density magnetic storage and logic devices.

The invention relates to a composite antiferromagnetic material with huge adjustable vertical exchange bias and a preparation method and application thereof. According to an embodiment, a composite antiferromagnetic material may include an alternately stacked structure of at least two antiferromagnetic layers including a Mn-based antiferromagnetic material selected from the group consisting of Ni 100-x Mnx, Fe 100-x Mnx, Pt 100-x Mnx, Ir 100-x Mnx, Pd 100-x Mnx, Cr 100-x Mnx, Ga 100-x Mnx, Sn 100-x Mnx, Cu 100-x Mnx, and Ge 100-x Mnx, different from each other, where x is greater than zero and less than 100, and x is greater than 0 and less than 100. The composite antiferromagnetic material provides a vertical exchange bias.

The invention discloses a preparation method of gamma-MnS with an exchange bias effect and stable at room temperature. According to the method, a normal-pressure chemical vapor deposition process is adopted, in the cooling stage after material growth is completed, sulfur vacancies are introduced into crystals by accurately controlling sulfur partial pressure and regulating and controlling the sulfur atmosphere where the material is located, and gamma-MnS which has the exchange bias effect and is stable at the room temperature is prepared. The EB effect is achieved through the sulfur vacancy induced intrinsic magnetic heterostructure in the single-phase gamma-MnS, dependence on an artificial heterogeneous interface is avoided, and potential application prospects are achieved in the field of development of next-generation high-performance, high-stability and low-power-consumption spin electronic devices and the like.

The present disclosure relates to the technical field of semiconductor devices and manufacturing technology thereof, in particular to a magnetic memory and a manufacturing method thereof, the magnetic memory comprising at least: an anti-ferromagnetic layer, a material of the anti-ferromagnetic layer being a non-collinear anti-ferromagnetic material; and a magnetic tunnel junction disposed on the anti-ferromagnetic layer, the magnetic tunnel junction comprising, from bottom to top, a free layer, a tunneling barrier layer and a reference layer; wherein when the anti-ferromagnetic layer is supplied with a current, a spin-orbit torque effect of the anti-ferromagnetic layer is utilized to change a direction of an exchange bias field formed by the anti-ferromagnetic layer and the free layer, and then to flip a magnetic moment direction of the free layer. The magnetic moment flipping can be achieved by means of the spin-orbit torque effect of the anti-ferromagnetic layer of the non-collinear anti-ferromagnetic material, so that the write-in current is greatly reduced, and the power consumption of the magnetic memory is reduced, and the magnetic memory is easier to drive.

The invention provides a semimetal compensation ferrimagnetic material, the chemical formula of the semimetal compensation ferrimagnetic material is CrFeS2, the semimetal compensation ferrimagnetic material has a hexagonal NiAs type crystal structure and belongs to a 194 space group, and a preparation method of the semimetal compensation ferrimagnetic material comprises the following steps: packaging Cr powder, Fe powder, a sulfur block and a transmission medium iodine in a vacuum quartz tube; and placing in a heating furnace, heating at 780-920 DEG C for 4-30 days, and then quenching to a greenhouse. The semimetal compensation ferromagnetic material provided by the invention simultaneously has the characteristics of great perpendicular magnetic anisotropy and magnetic compensation characteristic, so that the material can realize zero-field cold large exchange bias, and the direction of the exchange bias can be regulated and controlled by unidirectional magnetic fields with different sizes, so that the semimetal compensation ferromagnetic material has a wide application prospect in the field of spintronics.

A method for fabricating a magnetic material with tunable magnetic properties, comprising the reactive sputtering of a Mn3N2 seed layer onto a substrate, annealing at a first temperature, depositing a Mn layer onto the Mn3N2 seed layer, cooling to a second lower temperature, and applying a capping layer to complete the magnetic material. The resulting structure includes a Si substrate with one or more MnNx layer(s) with tunable nitrogen contents, and a capping layer, exhibiting adjustable magnetic properties such as exchange bias. A single Mn4N layer can be formed with this method, so can multilayers of Mn3N2 / Mn2N / Mn4N, or Mn2N / Mn4N, or other variations. Nitrogen partial pressure during deposition enables control of exchange bias by over an order of magnitude, while post-annealing reduces the bias by up to 70% through nitrogen migration into a neighboring tantalum layer. Voltage conditioning further tunes magnetic properties by driving nitrogen ions out of the Mn nitride layer, yielding an increased saturation magnetization and decreased exchange bias.

The invention discloses a magnetic Van der Waals film and a preparation method and application thereof, and particularly relates to the field of device preparation. Comprising the following steps: setting growth conditions, and sequentially epitaxially growing a preset number of layers of magnetic Van der Waals films on the surface of a substrate; wherein after each layer of magnetic Van der Waals film is obtained, in-situ RHEED, structure and intrinsic magnetism measurement is carried out on the magnetic Van der Waals film, and the mass of the magnetic Van der Waals film of the current layer is determined according to the measurement result; and when the quality reaches a preset condition, epitaxially growing a next layer of magnetic Van der Waals film. And preparing the magnetic Van der Waals film into a magnetic head exchange bias device by adopting a micro-nano etching technology, and carrying out transport measurement on the magnetic head exchange bias device. Based on the method, the magnetic Van der Waals film is used for preparing the magnetic head exchange bias device, and the thickness, the scale and the cleanliness of the interface of the magnetic head exchange bias device can be accurately controlled.

The present invention discloses a zero-field-cooled room-temperature exchange bias permanent magnet material, which is composed of two rare earth elements Pr and Gd, and Co element. First, a cast Pr-Gd-Co compound is obtained through melting, and then a Pr-Gd-Co thin strip, that is, the zero-field-cooled room-temperature exchange bias permanent magnet material, is obtained through melt spinning. The atomic ratio satisfies 1:3, and the chemical formula is Pr 1‑ x Gd x Co3, where the value range of x is 0.2 ≤ x ≤ 0.8; the Curie temperature ranges between -400 K and 550 K; the phase structure is a rhombohedral PuNi3-type crystal structure. Its preparation method includes: 1. Preparation of the cast Pr-Gd-Co compound; 2. Preparation of the zero-field-cooled room-temperature exchange bias permanent magnet material. As an application of the permanent magnet material, at room temperature, when the external magnetic field is 2 T, the coercivity is 1.37 - 12.88 kOe; the exchange bias field is 0.2 - 5.38 kOe; at 10 K, when the external magnetic field is 5 T, the coercivity is 16.47 - 36.23 kOe; the exchange bias field is 2.73 - 14.92 kOe. The advantages of the present invention are that it has large coercivity, strong exchange bias field under zero-field-cooled conditions, good temperature stability, and simple process.

The invention discloses a medium entropy alloy material with zero-field cold exchange bias effect and a preparation method thereof. The chemical formula of the material is Mn 2‑x FeCoNi, 0.2≤x≤0.4, firstly obtain Mn by repeated smelting 2‑x The FeCoNi alloy is then sealed in a vacuum quartz tube and placed in a muffle furnace for annealing. 2‑ x The FeCoNi medium-entropy alloy material has a zero-field cold exchange bias effect. The size of its ferromagnetic and antiferromagnetic exchange coupling can be controlled by changing the Mn composition (0.2≤x≤0.4) to obtain a specific antiferromagnetic and ferromagnetic coupling ratio, thereby obtaining an obvious zero-field cold exchange bias field without the need for an additional external magnetic field accompanying the cooling process. This material has potential application prospects in spin electronics fields such as magnetic storage units and spin valve devices.

The present disclosure generally relates to a two-dimensional magnetic recording (TDMR) read head. The TDMR read head comprises a first sensor, a second sensor, and a middle shield (MS) disposed between the first and second sensors. The MS comprises a seed layer, an IrMn layer disposed on the seed layer, an insertion layer comprising Ru or CoFe disposed on the IrMn layer, a first NiFe layer having a pinned magnetization, and a cap layer disposed over the first NiFe layer. In one embodiment, the MS further comprises an Ru layer disposed on the first NiFe layer and a second NiFe layer disposed on the Ru layer, the second NiFe layer having a pinned magnetization in a direction antiparallel to the first NiFe layer. The insertion layer comprising Ru decreases an exchange energy of the MS. The insertion layer comprising CoFe increases an exchange energy of the MS.

This invention discloses a two-dimensional van der Waals homogeneous structure with adjustable exchange bias, relating to the field of magnetic storage technology. The invention comprises a two-dimensional van der Waals ferromagnetic layer and a two-dimensional van der Waals antiferromagnetic layer stacked on top of each other. The thickness of both the ferromagnetic and antiferromagnetic layers is 2-200 nm, and the thickness ratio of the ferromagnetic and antiferromagnetic layers is x:(1-x), where x ranges from 0.1 to 0.9. The beneficial effect of this invention is that existing exchange bias methods are difficult to control in terms of bias magnitude. Even when an exchange bias can be induced, the magnitude of the exchange bias field cannot be controlled. This invention achieves and controls the exchange bias magnitude by adjusting the relative proportion of the thicknesses of the ferromagnetic and antiferromagnetic layers. The higher the proportion of the antiferromagnetic layer, the larger the exchange bias field.

The invention relates to the technical field of magnetic recording media and magnetic multifunctional materials, in particular to double perovskite oxide ceramic with an exchange bias effect and a preparation method of the double perovskite oxide ceramic. The chemical formula of the ceramic is Nd2-xSrxCoMnO6, the molar doping amount x of Sr < 2 + > is more than or equal to 0.0 and less than or equal to 0.5, and the ceramic has a single-phase orthogonal structure. The preparation method comprises the following steps: proportionally mixing the raw materials, and sintering in three stages to obtain the ceramic. When Sr < 2 + > is not doped, the oxygen vacancy defect causes a spin structure change and causes an exchange bias effect, under a 1kOe cooling magnetic field, the exchange bias field is 2.8 kOe, and the exchange bias does not have a magnetic exercise effect; when Sr < 2 + > is doped, the crystal structure and the spin structure change, the exchange bias field is 2.1-3.6 kOe, and the Curie temperature is 128-141K. The ceramic is stable in performance, the preparation process is simple and easy to control, and the ceramic is suitable for industrial production and suitable for the field of electronic components such as high-density magnetic storage.

The invention relates to the technical field of magnetic photoelectric detection, in particular to a thin film device with bias field exchange and photoelectric detection performance and a preparation method thereof, and the thin film device comprises a substrate layer, an antiferromagnetic semiconductor layer, a ferromagnetic semiconductor layer and an electrode layer which are sequentially stacked from bottom to top; materials of the antiferromagnetic semiconductor layer and the ferromagnetic semiconductor layer have a photoelectric effect. The thin film device not only has good photoelectric detection performance, but also has a strong exchange bias field; the exchange bias phenomenon comes from a double-layer film structure of an antiferromagnetic semiconductor layer and a ferromagnetic semiconductor layer, the magnetic moment of the ferromagnetic semiconductor layer is directly coupled with the magnetic moment which is not counteracted at the magnetic moment interface of the antiferromagnetic semiconductor layer, so that the ferromagnetic semiconductor layer is pinned, and the exchange bias phenomenon is formed; when the ferromagnetic semiconductor layer and the antiferromagnetic semiconductor layer are made of materials with photoelectric effects, the thin film not only has an exchange bias field, but also has certain photoelectric detection capability.

The invention discloses a magnetoresistive element, a preparation method thereof and sensing equipment, and relates to the technical field of magnetic sensors. The magnetoresistive element comprises a plurality of magnetoresistive sub-elements; the magnetic resistance sub-element comprises a free layer, a pinned layer, a tunneling layer, a pinning layer and a regulation and control layer; the free layer has a variable magnetic field direction under an external magnetic field; the pinned layer has a fixed magnetization direction under an external magnetic field in a preset magnetic field range; the tunneling layer is arranged between the free layer and the pinned layer; the pinning layer is arranged on the side, away from the tunneling layer, of the pinned layer, the pinning layer and the pinned layer have exchange bias coupling, and the magnetization direction of the pinned layer is fixed through the exchange bias coupling; the regulation and control layer is arranged between the pinned layer and the tunneling layer and is used for generating spin current when preset current is introduced, so that the pinned layer and the pinned layer have exchange bias coupling. According to the invention, the pinning layer and the pinned layer can be induced to form exchange bias only by the spin current by using the spin orbit moment effect, so that the preparation efficiency of the magnetoresistive element is improved.

The invention discloses a preparation method of a permanent magnet material with an exchange bias effect. The method comprises the following steps: weighing a Pr-Al-Cu alloy raw material, smelting, ball-milling, mixing with an organic solvent to prepare a diffusion source, uniformly coating the surface of a neodymium-iron-boron magnet with the diffusion source, and completing two-stage gradient diffusion heat treatment in a vacuum atmosphere. According to the neodymium-iron-boron magnet subjected to diffusion treatment, it is found through tests that a continuous and compact non-magnetic grain boundary phase is formed at the grain boundary of the diffused neodymium-iron-boron magnet, meanwhile, under the action of an external magnetic field, an antiferromagnetic grain boundary phase Pr6Fe13Cu generates a strong magnetic moment pinning effect on a main phase Nd2Fe14B, and then a reverse external magnetic field needed by ferromagnetic phase magnetic moment inversion is improved; therefore, an exchange bias phenomenon is generated, and the coercive force of the neodymium-iron-boron magnet is effectively improved. The method is well compatible with existing grain boundary diffusion process equipment, does not need additional transformation cost, is easy to implement industrially, is relatively low in cost, and can effectively improve the thermal stability of the magnet.

The application relates to a magnetic memory, comprising: an MTJ device, comprising a first electrode, an MTJ layer and an AFM layer, the MTJ layer being arranged between the first electrode and the AFM layer; a second electrode, arranged on a side of the AFM layer away from the MTJ layer; and a heater, arranged on a side of the second electrode away from the AFM layer, used for heating the AFM layer to demagnetize the AFM layer; wherein in a write mode, a write current flows from one end of the second electrode to the other end. The magnetic memory places the heater on the side of the second electrode away from the AFM layer to heat the AFM layer, which can effectively demagnetize the AFM layer completely; after demagnetization, the magnetization direction of the AFM layer is determined by the SOT effect generated by the write current passing through the bottom electrode, and then the exchange bias between the AFM layer and the free layer is flipped, so that the magnetic moment of the free layer is flipped. The demagnetization of the AFM layer adopts the heat generated by the separate heater, and does not need to demagnetize the AFM layer through the Joule effect of the increased write current, so that the write power consumption of the storage chip is effectively reduced.

The invention discloses a voltage regulation and control magnetic memory based on a two-dimensional ferromagnetic / multiferroic heterostructure and a preparation method, the device is composed of a substrate, a multiferroic thin film layer, a two-dimensional ferromagnetic thin film layer, an upper electrode and a lower electrode, an uncompensated magnetic moment is generated on an interface through ferroelectric polarization of the multiferroic layer, and the uncompensated magnetic moment and the two-dimensional ferromagnetic layer form exchange bias. And the ferroelectric polarization direction can be reversed by applying low voltage, so that the external magnetic field-free and nonvolatile regulation and control of the magnetization of the two-dimensional ferromagnetic layer are realized. The preparation method comprises the steps of magnetron sputtering growth of the multiferroic thin film, interface annealing treatment, molecular beam epitaxial growth of the two-dimensional ferromagnetic thin film and electrode preparation. The device has strong interface coupling, low power consumption, high regulation and control amplitude and good cycling stability at room temperature, wide-range voltage regulation and control of exchange bias can be realized, and a reliable technical scheme is provided for a novel low-power-consumption nonvolatile memory.

This invention relates to a magnetic tunnel junction memory cell based on magnetic skyrmions and its operation method. A magnetic tunnel junction memory cell may include: a reference magnetic layer and a free magnetic layer separated by a barrier layer; a skyrmion carrier layer separated from the free magnetic layer by a spacer layer, the spacer layer inducing ferromagnetic coupling or antiferromagnetic coupling between the skyrmion carrier layer and the free magnetic layer; and a cap layer formed on the skyrmion carrier layer, the cap layer applying a bias magnetic field to the skyrmion carrier layer by an exchange bias, such that the skyrmion carrier layer is in the skyrmion phase, wherein the cap layer generates a spin current when an in-plane write current is applied, the spin current being vertically injected into the skyrmion carrier layer to write skyrmions, and the skyrmions being coupled to the free magnetic layer through ferromagnetic coupling or antiferromagnetic coupling induced by the spacer layer.