15 results about "Magnetization reversal" patented technology

This application discloses a magnetic tunnel junction memory device based on a bismuth selenide and nickel iodide heterojunction substrate. The memory includes, from top to bottom, a top electrode, a SOT-MTJ, and a substrate. The SOT-MTJ includes, from top to bottom, a reference layer, a tunneling layer, a heavy metal layer, and a free layer. The substrate is a Bi2Se3 and NiI2 heterojunction structure. Bi2Se3 facilitates the conversion of current into spin-orbit torque, enabling current-induced field-free magnetization reversal. NiI2 has vertical magnetic anisotropy, which can reduce the critical reversal current. An artificial antiferromagnetic structure (CoFeB / MgO / Ta / W / CoFeB) with vertical magnetic anisotropy is adopted, with Ta / W composite heavy metal as the coupling layer. The two antiferromagnetically coupled CoFeB layers switch between parallel and antiparallel states under the action of SOT. Both Ta and W have large spin Hall angles, which are very beneficial for generating spin-orbit torque to reverse the magnetic moment.

A columnar three-dimensional magnetic storage unit and a writing method are disclosed. In the magnetic storage unit, a central nanopillar is a nanopillar structure made of a material having a spin-orbit coupling effect; a magnetic storage layer wraps an outer side of the central nanopillar; a magnetic free layer surrounds and contacts the central nanopillar, with a polarization direction of the magnetic free layer extending axially along the nanopillar structure, and the magnetization reversal of the magnetic free layer depending on spin-polarized electrons, whose polarization direction is circumferential, generated by the central nanopillar, a damping-like torque and a field-like torque generated by the spin-polarized electrons synergistically achieving the magnetization precessional reversal of the magnetic free layer; a magnetic tunneling layer wraps an outer side of the magnetic free layer; a magnetic pinned layer wraps an outer side of the magnetic tunneling layer.

To provide a magnetic recording medium capable of improving magnetization inversion efficiency without giving new magnetization inversion energy with a simple structure, and to provide a magnetic recording device provided with the same.SOLUTION: According to an aspect of the present invention, there is provided a magnetic recording medium 10 capable of recording information by irradiation with circularly polarized light, the magnetic recording medium 10 including a substrate 11, an antiferromagnetic layer 12 provided on one surface side of the substrate 11, and a ferromagnetic layer 13 provided on a surface 12B of the antiferromagnetic layer 12 opposite to a surface 12A on the substrate 11 side.SELECTED DRAWING: Figure 2

The invention discloses a zero-field spin-orbit moment memory with a ferromagnetic layer component gradient structure and a preparation method thereof, the core structure of the memory comprises a CoFeB ferromagnetic layer with a vertical component gradient, and magnetic moments at two sides of a domain wall generate asymmetry in amplitude or orientation by regulating and controlling gradient distribution of Co, Fe and B elements and inducing non-uniform Dzyaloshiski-Moriya interaction (DMI); furthermore, domain wall chiral characteristics are weakened, a net effective field is formed, and deterministic magnetization overturning without assistance of an external magnetic field is finally realized. In the preparation process, a magnetron sputtering technology is adopted, a heavy metal strong spin orbit coupling layer, a vertical magnetic anisotropy magnetic free layer with component gradient, a tunnel barrier layer, a magnetic vertical reference layer, an artificial antiferromagnetic pinning layer and a covering layer are stacked in sequence, and a magnetic tunnel junction (MTJ) unit is prepared through annealing and micro-nano processing technologies. The invention provides an efficient solution for the research and development of controllable magnetic memories and logic devices, and has a wide application prospect in the field of high-density magnetic memories.

This application discloses a signal readout method and apparatus based on a Hall effect device array with lateral resistance, relating to the field of circuit technology. Each Hall effect device is provided with two power supply terminals and at least one Hall signal terminal. The method includes: changing the flip angle of the free magnetic layer of at least one Hall effect device using spin orbital moment, thereby setting the Hall resistance value of the corresponding Hall effect device to a desired target value; connecting the Hall signal terminals of several Hall effect devices in series to read the summed voltage; and connecting the Hall signal terminals of several Hall effect devices in parallel to read the summed current. The Hall effect device of this application can achieve current-induced out-of-plane magnetization reversal under shunt conditions; the flip angle can change the resistance value, thereby reducing the need for Hall effect devices with different resistance values; this application realizes that the Hall signal terminals of multiple Hall effect devices are connected in series to achieve voltage summation, or connected in parallel to achieve current summation.

This allows for even greater spin-orbit torque to be generated in SrRuO3. [Solution] This current-induced magnetization reversal element comprises a substrate 101 and a thin film 102 made of SrRuO3 crystals epitaxially grown on the substrate 101. The substrate 101 is made of a crystal whose lattice constant differs by 0.5% or more from the lattice constant of the pseudo-cubic crystal of SrRuO3, and whose main surface on which the thin film 102 is formed is a cubic (001) or pseudo-cubic (001) plane. In the thin film 102, the oxygen octahedron is rotated with respect to the crystal axis of the pseudo-cubic crystal of SrRuO3.

The application relates to a magnetic multilayer film and a preparation method and application thereof. The magnetic multilayer film comprises a substrate and a heavy metal layer, a ferromagnetic layer, a rare earth magnetic alloy layer, a rare earth metal layer, a light metal layer and a protective cover layer which are sequentially arranged on the substrate; the heavy metal layer is configured to generate spin current under the action of current and acts on the ferromagnetic layer in the form of spin-orbit torque; the light metal layer is configured to generate orbital current under the action of current; the rare earth metal layer and the rare earth magnetic alloy layer are configured to convert the orbital current into orbital torque and act on the rare earth magnetic alloy layer; the orbital torque and the spin-orbit torque synergistically act to reduce the critical current of magnetization reversal of the magnetic multilayer film. The magnetic multilayer film of the application realizes orbital torque synergistic driving, significantly reduces the critical current of magnetization reversal of the device, and is beneficial to the preparation of high-efficiency and low-power-consumption spintronic devices.

Disclosed methods include placing a semiconductor wafer containing MRAM devices into a first magnetic field that has a magnitude sufficient to magnetically polarize MRAM bits and has a substantially uniform field strength and direction over the entire area of the wafer. The method further includes placing the wafer in a second magnetic field having an opposite field direction, a substantially uniform field strength and direction over the entire area of the wafer, and magnitude less than a design threshold for MRAM bit magnetization reversal. The method further includes determining a presence of malfunctioning MRAM bits by determining that such malfunctioning MRAM bits have a magnetic polarization that was reversed due to exposure to the second magnetic field. Malfunctioning MRAM bits may further be characterized by electrically reading data bits, or by using a chip probe to read one or more of voltage, current, resistances, etc., of the MRAM devices.

This invention provides an orbital moment magnetic memory and its fabrication method. The orbital moment magnetic memory includes, from bottom to top, a substrate, an orbital Hall layer, a free layer, a barrier layer, and a fixing layer. The orbital Hall layer includes a metal layer and an FeMn layer arranged vertically. The free layer includes a first Co2Fe6B2 layer and an Fe3GaTe2 layer arranged vertically. The fixing layer includes a [Co / Pt] layer arranged vertically. n The structure consists of a first layer, a Ta layer, and a second Co2Fe6B2 layer. This structure utilizes the orbital Hall layer to efficiently generate orbital current, exchange bias field, and stray field, and leverages the strong spin-orbit coupling characteristics of the Fe3GaTe2 layer to achieve spin polarization and magnetization reversal at low current. This orbital-moment magnetic memory not only maintains a fast write speed while reducing power consumption, but also exhibits superior performance in high-speed data access, providing fundamental support for future applications in orbital electronics, magnetic storage, and other fields.

The invention discloses a magnetic storage array and a read-write method, in the magnetic storage array, a plurality of magnetic storage devices are arranged along an X-Y plane, and each word line simultaneously wraps the outer sides of a plurality of gates; each bit line is connected with the tops of the plurality of column electrodes; drain electrodes of the plurality of CMOS transistors are connected with the bottom of the column electrode; the grid line is connected with grid electrodes of the plurality of CMOS transistors; the source line is connected with the source electrodes of the plurality of CMOS transistors; magnetization overturning of a magnetic free layer of the magnetic tunnel junction is completed through the combined action of a spin-orbit moment and a spin-transfer moment, the spin-orbit moment is provided by spin-polarized electrons, the polarization direction of the spin-polarized electrons is the circumferential direction, generated by current passing through a column electrode, and the spin-transfer moment is provided by injecting write current in the radial direction of the magnetic tunnel junction. The judgment of the resistance state of the magnetic tunnel junction in the magnetic storage array is completed by injecting read current along the radial direction of the magnetic tunnel junction.

The invention provides a magnetization state detection system and method for a hard magnetic material, and relates to the technical field of magnetization state detection. Identifying a target magnetic flux density area from the magnetic flux density distribution diagram, and positioning the output end of the local excitation probe to a physical feature point corresponding to the target magnetic flux density area on the to-be-detected surface of the hard magnetic material; applying a local reverse magnetic field to the physical feature points, and obtaining a local magnetization reversal curve at the physical feature points; extracting a characteristic parameter representing the coercive force of the physical characteristic point from the local magnetization inversion curve, and if the attenuation percentage of the characteristic parameter relative to the reference coercive force parameter exceeds a second preset threshold value, determining that the area where the physical characteristic point is located is a demagnetized area; and outputting a magnetization state detection map of the hard magnetic material based on the demagnetized region. According to the invention, the precise positioning of the demagnetization area can be realized when the magnetic domain structure of the hard magnetic material generates local irreversible change.

The present invention provides a magnetic memory device with a simple structure, excellent ease of operation, and compatibility with semiconductor manufacturing processes, while simultaneously achieving both magnetization reversal under zero magnetic field conditions and low critical current density. [Solution] The magnetic memory device 10 comprises a channel layer 11 that generates a spin current or orbital current when an electric current is supplied, and a magnetic layer 12 disposed on one side of the channel layer 11 and whose magnetization direction can be reversed by the spin current, wherein the channel layer 12 contains maxines (MXenes) having a composition ratio represented by the following formula (1). M n+1 X n ...(1) In equation (1) above, M represents a transition metal, X represents carbon or nitrogen, and n represents an integer of 1 or more.

The present application provides a magnetic head and a magnetic recording and reproducing apparatus in which the deterioration of a spin torque control element can be easily known. The magnetic head according to an embodiment includes a main pole, an auxiliary pole disposed apart from the main pole by a write gap, a spin torque control element disposed in the write gap, a bias current control section that supplies a bias current to the spin torque control element, and a resistance measurement section that measures a resistance value of the spin torque control element, wherein the difference between a first resistance value when the bias current is supplied with a polarity opposite to the polarity of the magnetization reversal of the spin torque control element and a second resistance value when the bias current is supplied with the polarity of the magnetization reversal of the spin torque control element is 4% or less.

This magnetic memory element comprises: a ferromagnetic layer having reversible magnetization; and a ferroelectric layer laminated with the ferromagnetic layer and having a polarization direction component in a lamination direction, wherein the ease of magnetization reversal of the ferromagnetic layer differs between a state in which the polarization direction of the ferroelectric layer is in a first polarization direction and a state in which the polarization direction is in a second polarization direction different from the first polarization direction.

The invention discloses a spin valve device based on ferroelectric metal. The spin valve device comprises a top electrode, a first ferromagnetic layer, a ferroelectric metal layer, a second ferromagnetic layer and a bottom electrode which are sequentially stacked from top to bottom. Wherein the ferroelectric metal layer has ferroelectricity and metal conductivity at the same time, and is in direct contact with the upper ferromagnetic layer and the lower ferromagnetic layer to form an interface magnetoelectric coupling effect. Based on the core structure, the invention provides two nonvolatile memories, namely an STT type memory and an SOT type memory, the STT type memory performs writing by utilizing a spin-transfer torque effect, and the SOT type memory performs writing on a bottom heavy metal layer by utilizing a spin-orbit torque effect. Voltage pulses are applied to the ferroelectric metal layer to regulate and control the polarization state of the ferroelectric metal layer, so that magnetization overturning of the second ferromagnetic layer can be effectively assisted to reduce write-in power consumption; different polarization states of the ferroelectric metal layer are combined with different magnetization states of the ferromagnetic layer, so that a plurality of distinguishable resistance states can be formed, and multi-state information storage is realized.