39 results about "Spontaneous magnetization" patented technology

In a magnetic random access memory, a memory cell includes a magnetic field generating section having an extension wiring line, and connected with a first selected bit line, a conductive pattern, and a magnetic resistance element having a spontaneous magnetization, storing a data and connected between the extension wiring line and the conductive pattern. In a data write operation into the memory cell, a write data is written in the magnetic resistance element of the memory cell by a write electric current which flows through the extension wiring line of the magnetic field generating section of the memory cell, and a value of the write data is determined based on a direction of the write electric current. In a data read operation from the memory cell, a read electric current flows through the extension wiring line of the magnetic field generating section and the magnetic resistance element in the memory cell. A memory cell array section includes the memory cells arranged in a matrix, and each memory cell is connected with a first word line and a first bit line at least, the gate section.

An MRAM has a plurality of bit lines, a reference bit line, a plurality of memory cells and reference cells and a read section. The memory cells are provided along the bit lines and the reference cells along the reference bit line. The memory cell and reference cell have a tunneling magnetic resistance and a reference tunneling magnetic resistance, each of which has a spontaneous magnetization whose direction is reversed in accordance with data stored therein. The read section has a first resistance section which contains a ninth terminal connected with a bit line and a tenth terminal connected with the first power supply, a second resistance section which contains an eleventh terminal connected with the reference bit line and a twelfth terminal connected with the first power supply, and a comparing section which compares a sense voltage on the ninth terminal and a reference voltage of the eleventh terminal.

A shim adapted for altering a magnetic field of a magnet includes a first material which exhibits an increase in spontaneous magnetization with an increase in temperature for a predetermined temperature range.

The invention relates to a 5-methyl-1H-tetrazole and isophthalic acid mixed ligand cobalt (II) coordination polymer magnetic material, and a preparation method and application thereof. The chemical formula of the coordination polymer magnetic material provided by the invention is {[Co7(H2O)2(mu3-OH)4(mtz)2(ip)4].13/4H2O}, wherein mtz is the 5-methyl tetrazole anion with valence of -1, and ip is the isophthalic acid anion with valence of -2. The coordination polymer magnetic material is prepared by solvothermal synthesis, and is high in productivity and good in reproducibility. The coordination polymer magnetic material is the three-dimensional cobalt (II) compound simultaneously including 5-methyl-1H-tetrazole and isophthalic acid mixed ligand, presents continuous two-step field-induced metamagnetic transition and spin-flop transition, which are from antiferromagnetic order to week spontaneous magnetization, in different external magnetic fields, and can be used as molecular-based magnetic material to have great application value in the field of material science.

The invention relates to a mixed valence copper (I/II) complex magnetic material containing a 1, 2, 4-triazole and 5-isophthalic acid mixing ligand as well as a preparation method and an application thereof. The chemical formula of the complex magnetic material is [CuI0.5CuII1.5(H2O) (trz)2(H0.5nip)], wherein trz is a 1, 2, 4-triazole-valence anion, and H0.5nip is a 5-isophthalic acid-1.5 valence anion. The complex magnetic material is prepared by adopting a hydrothermal method and has higher yield and good repeatability. The complex magnetic material is a mixed valence copper (I/II) complex simultaneously containing the 1, 2, 4-triazole and 5-isophthalic acid ligand, has the remarkable spontaneous magnetization behavior at a low temperature, can be taken as a molecule-based magnetic material and has huge application value in the field of materials science.

The invention relates to a 5-methyl-1H-tetrazole/1,2,3-trimesic acid mixed ligand cobalt (II) complex magnetic material, and a preparation method and application thereof. The chemical formula of the complex magnetic material is [Co2(H2O)(mtz)(btc)], wherein mtz is a 5-methyltetrazole -1-valent anion, and btc is a 1,2,3-trimesic acid -3-valent anion. The complex magnetic material is prepared by a hydrothermal method, and has the advantages of high yield and favorable repeatability. The complex magnetic material is a cobalt (II) complex simultaneously containing 5-methyl-1H-tetrazole 1,2,3-trimesic acid mixed ligand; and the complex magnetic material has obvious spontaneous magnetization behavior at low temperature, and has huge application value as a molecule-base magnetic material in the field of material science.

The invention discloses a test technique of magnetic material, which is characterized by the following: placing the detected sample film in the extra DC magnetic field; paralleling the detected sample film plane to the extra magnetic field direction; rotating the detected sample film around the vertical axle of plane; making the detected film reach magnet saturation and extra magnet field between saturated field and coercive field; keeping the magnet field; rotating the detected sample at certain angle; measuring the spontaneous magnetization strength MS and corresponding projection value M in the ª’0 condition; calculating the M value function corresponding to different ª’0.

Provided is a noninvasive measuring method for rapid temperature variation under a DC excitation magnetic field, comprising: (1) positioning ferromagnetic particles at a measured object; (2) applying a DC magnetic field to area of the ferromagnetic particles enabling the ferromagnetic particles to reach saturation magnetization state; (3) obtaining steady temperature T₁ of the measured object at room temperature, and calculating initial spontaneous magnetization M₁, of the ferromagnetic particles according to the steady temperature T₁; (4) detecting amplitude A of a magnetization variation signal of the ferromagnetic particles after temperature of the measured object varies, and calculating temperature T₂ after change according to the amplitude A of the magnetization variation signal; and (5) calculating temperature variation ΔT=T₂-T₁ according to the temperature T₂ after change and the steady temperature T₁. The present invention can realize noninvasive temperature measurement with high speed and high accuracy so as to resolve technical problems of low speed and low precision.

A method of magnetization reversal, time stable ferrimagnetic material, a product and a domain comprising said material, a system for magnetization reversal, and information storage. Therein, a ferrimagnetic material is one in which magnetic moments of the atoms on different sublattices are opposed, as in antiferromagnetism; however, in ferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains.

The invention discloses a magnetic thermosensitive material manganese-doped holmium iron oxide as well as preparation methods of monocrystalline and polycrystalline thereof. A solid reaction method is carried out with Ho2O3, MnO2 and Fe2O3 powder for synthesis of a HoFe1-xMnxO3 polycrystalline material, and the polycrystalline material grows into a monocrystalline material by an optical-floating-zone furnace method. Applied magnetic fields are not needed for assisting the magnetic thermosensitive material, magnetic transition temperature has a high susceptibility, the magnetic transition critical temperature can be adjusted for usage of the material at room temperature, and the material can be applied to a magnetic thermosensitive device. Ratio of the magnetic thermosensitive material can be changed, in order to obtain different materials whose magnetic transition critical temperature range is between -213.15 to 29.17 DEG C, so that the magnetic transition speed of the material is higher than the magnetic transition speed of the traditional material whose magnetic transition critical temperature is around the Curie temperature, and spontaneous magnetization happens at the temperature above the critical temperature, so that applied magnetic fields are not needed for induction before and after transition. The magnetic thermosensitive material is better than the traditional magnetic thermosensitive device material whose magnetic transition depends on the Curie temperature.

A technique is provided in which an offset magnetic field of a memory cell of a MRAM is reduced more effectively. The MRAM of the present invention is composed of a free layer (11) which has a reversible free spontaneous magnetization, a fixed layer (6) which has fixed spontaneous magnetization, and a spacer layer (10) formed of non-magnetic interposed between the free layer (11) and the fixed layer (6). The fixed layer (6) is formed such that orange peel effect and magneto-static coupling effect does not substantially influence on the free layer (11).

The invention relates to a magnetic measurement method, in particular to a method for testing a hard and easy magnetization direction of a magnetic film material with exchange bias. The method comprises the following steps of: arranging a sample film to be tested in an external direct current magnetic field, so that a plane of the sample film to be tested is parallel to the direction of the external magnetic field; rotating the sample film to be tested around an axis vertical to the plane; during test, optionally applying a given external magnetic field, keeping the magnetic field invariable, and recording an initial position of the sample and magnetization at the moment; rotating the sample film to be tested at an angle, and measuring a corresponding projection value M of spontaneous magnetization MS of the film to be tested in the direction of the external magnetic field at the angle theta0 so as to obtain a function of the sample film to be tested at different rotating angles theta0 and corresponding M values; and determining an easy magnetization axis or a hard magnetization axis of the exchange bias film according to a measured M-theta0 curve.

A three-dimensional (3D) in-plane magnetic sensor includes a first magnetic sensor, a second magnetic sensor, a third magnetic sensor and a circuit. The first magnetic sensor, second magnetic sensor and third magnetic sensor are installed on a same plane to measure the magnetic field component of first direction, second direction and third direction, where the third direction is perpendicular to the first and second direction. The third magnetic sensor includes a third fixed layer, a third magnetic insulating layer and a third free layer. The magnetoresistance of the third free layer is an intermediate value in the spontaneous magnetization direction, and is varied when interfered by an external magnetic field. In short, the 3D in-plane magnetic sensor is manufactured with semiconductor processing which does not require vertical adhesion, and also bring the benefits of improved production capacity, prolonged product life, reduced manufacturing cost and time.

The invention provides an MOFs (Metal Organic Frameworks) material. The chemical formula of the MOFs material is Co3RE4(TZI) 6.9H2O, RE comprises at least one of Gd, Sm, Eu, Tb and Dy, and TZI3- in the Co3RE4 (TZI) 6.9H2O is a trivalent anion of 5-(1-H-tetrazole)-isophthalic acid. Co and 4f rare earth metals are used as magnetic center atoms; the MOFs material obtained by taking 5-(1-H-tetrazole)-isophthalic acid as a ligand has a porous structure in a three-dimensional space; an asymmetric unit of the crystal is hourglass-shaped; Co ions and adjacent rare earth metal ions act to spontaneouslymagnetize, electronic magnetic moments are arranged in the same direction, and the spontaneous magnetization intensity of the other asymmetric unit in the same unit cell is equal to that of the former and opposite to that of the former, so that the net magnetic moment of the whole unit cell is zero, and the magnetic moment of the whole crystal is in an ordered state and is anti-ferromagnetic.