41 results about "Exchange bias" patented technology

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.

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.

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.

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 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 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.

The application discloses a three-dimensional spin Hall nano oscillator series-parallel array and a preparation method, wherein the array comprises a plurality of spin Hall nano microwave oscillator units of double-layer and / or three-layer film structures; the plurality of units are arranged in stacks to form a three-dimensional spin Hall nano oscillator series-parallel array; current passes through the left and right electrodes into the oscillator, is converted into a spin current in a strong spin-orbital coupling layer, and acts on a ferromagnetic layer magnetic moment; high-frequency precession of the magnetic moment causes a periodical change of the device resistance through a magnetoresistance effect; under the assistance of a spontaneous exchange bias field generated by exchange coupling effect, a microwave signal is output. The application uses an exchange bias field generated by exchange coupling effect between an anti-ferromagnetic layer and a ferromagnetic layer to replace an external magnetic field, reduces complexity of application, and on the other hand, adopts a three-dimensional spin Hall nano oscillator series-parallel array method to greatly improve output signal power, and can be widely applied to the fields of information communication and radio frequency technology.

The present invention provides a tunneling magnetoresistance and a manufacturing method thereof. The tunneling magnetoresistance includes: a first pinned layer; a free layer disposed opposite to the first pinned layer; a tunneling barrier layer located between the first pinned layer and the free layer; and a second pinned layer located on a side of the free layer facing away from the tunneling barrier layer. The second pinned layer can provide a weak exchange bias field for the free layer. After the external environmental temperature or the external magnetic field is removed, the exchange bias field can pin the direction of the free layer in the initial state, thereby avoiding the problem that the initial state of the vortex magnetization of the tunneling magnetoresistance is unstable and is easily affected by changes in the external environment, resulting in the drift of the magnetization curve. It has the effect of stabilizing the free layer and increasing the temperature stability of the free layer.

The invention provides a magnetic memory device and an information storage method, and the information storage method comprises the steps: generating an exchange bias field through the exchange coupling effect between an antiferromagnetic layer and a ferromagnetic free layer; the heat stability of the vertical magnetic moment is enhanced through the exchange bias field; wherein the vertical magnetic moment is a carrier for information storage; applying an external charge current to the antiferromagnetic layer to generate an out-of-plane spin polarization current; and overturning the vertical magnetic moment through the out-of-plane spin polarization current to store information. According to the invention, the thermal stability and the writing efficiency of the magnetic memory device can be greatly improved, the magnetization overturning process is simplified, the complexity and the power consumption of the system are reduced, and technical support is provided for the development of the next-generation high-density and low-power-consumption magnetic memory device.

A double pinned magnetoresistance (MR) multilayer film, a full bridge MR sensor using the double pinned MR multilayer film and a method for manufacturing the full bridge MR sensor are provided in the present invention. The double pinned MR multilayer film comprises: a buffer layer, a first antiferromagnetic layer, a first ferromagnetic layer, a first interlayer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second interlayer, a second ferromagnetic layer, a second antiferromagnetic layer and a cover layer that are stacked in sequence. The first antiferromagnetic layer applies a first exchange bias to the first ferromagnetic layer, and the first ferromagnetic layer applies a first artificial antiferromagnetic coupling to the ferromagnetic reference layer through the first interlayer. The second antiferromagnetic layer applies a second exchange bias to the second ferromagnetic layer, and the second ferromagnetic layer applies a second artificial antiferromagnetic coupling to the ferromagnetic free layer through the second interlayer. The full bridge MR sensor can not only realize the full bridge function in a single chip, but also has small zero point, simple annealing process and low cost through two global annealing.

The application belongs to the field of spin electronics and information technology, and provides a chiral / magnetic heterojunction device with exchange bias effect and a preparation method thereof, which comprises a substrate, a ferromagnetic material layer and a chiral material layer, and the ferromagnetic material layer and the chiral material layer are directly contacted and stacked and then placed above the substrate. Different chiral configurations of the chiral material layer correspond to different polarities of the exchange bias effect. The realization of the exchange bias effect is not limited by the types and preparation sequences of the ferromagnetic material layer and the chiral material layer, and through selection of chiral material layers with different configurations, the customized regulation and control of the polarity of the exchange bias effect can be realized, thereby providing a novel and feasible technical approach for realizing high-stability exchange bias effect.

The invention provides a preparation method of a Pr-Fe-B permanent magnet material with an exchange bias phenomenon, which comprises the following steps: weighing Pr, Fe, Cu and B according to the stoichiometric ratio of 70at% of Pr2Fe14B and 30at% of Pr6Fe13Cu, additionally adding 1wt% of Pr, carrying out electric arc melting, carrying out induction heating, spraying on a copper roller, crushing an obtained Pr2Fe14B-Pr6Fe13Cu alloy thin strip, and carrying out SPS sintering to obtain the Pr-Fe-B permanent magnet material. By adjusting the proportion of the alloy Pr2Fe14B to the alloy Pr6Fe13Cu, a continuous and thick non-magnetic grain boundary phase is formed in the grain boundary of the magnet, and the coercive force is greatly increased through decoupling intergranular exchange. And meanwhile, under the action of an external magnetic field, the antiferromagnetic phase Pr6Fe13Cu in the grain boundary generates a pinning effect on the main phase Pr2Fe14B, so that a larger reverse external magnetic field must be applied to realize complete overturning of the magnetic moment of the ferromagnetic phase, the exchange bias phenomenon is caused, and the coercive force of the magnet is improved. In addition, based on the advantages of low sintering temperature, short sintering time and the like of a discharge plasma rapid sintering technology, rapid growth of grains can be inhibited in the sintering process, so that grain refinement is realized.