48results about "Antiferromagnetic materials" patented technology

Provided herein are systems, methods, and compositions for magnetic nanoparticles and bulk nanocomposite magnets.

A structure of a magnet wherein a magnet consisting of a magnetic body including iron and rare earths, a plurality of fluorine compound layers or oxyfluorine compound layers are formed interior of the magnetic body, and the fluorine compound layer or oxyfluorine compound layer has a major axis which is greater than the mean particle size of the crystal grains of the magnetic body.

An alloy made of heat treated material represented by Gd₅(Si_xGe_1−x)₄ where 0.47≦x≦0.56 that exhibits a magnetic entropy change (−ΔS_m) of at least 16 J/kg K, a magnetostriction of at least 2000 parts per million, and a magnetoresistance of at least 5 percent at a temperature of about 300K and below, and method of heat treating the material between 800 to 1600 degrees C. for a time to this end.

A manganese oxide material has MnO3 as a matrix. It is an antiferromagnetic insulator and, when subjected to an electrical current or electric field, it is transformed into a ferromagnetic metal.

A ferromagnetic shape memory alloy comprising 25-50 atomic % of Mn, 5-18 atomic % in total of at least one metal selected from the group consisting of In, Sn and Sb, and 0.1-15 atomic % of Co and/or Fe, the balance being Ni and inevitable impurities, which has excellent shape memory characteristics in a practical temperature range, thereby recovering its shape by a magnetic change caused by a magnetic-field-induced reverse transformation in a practical temperature range.

A magnetic sensor includes a magnetoresistive effect element having a sensitivity axis in a specific direction. The magnetoresistive effect element has on a substrate, a laminate structure in which a fixed magnetic layer and a free magnetic layer are laminated with a nonmagnetic material layer interposed therebetween and includes at a side of the free magnetic layer apart from the nonmagnetic material layer, a first antiferromagnetic layer which generates an exchange coupling bias with the free magnetic layer and aligns a magnetization direction thereof in a predetermined direction in a magnetization changeable state. The free magnetic layer includes a first ferromagnetic layer in contact with the first antiferromagnetic layer to be exchange-coupled therewith and a magnetic adjustment layer at a side of the first ferromagnetic layer apart from the first antiferromagnetic layer. The magnetic adjustment layer contains at least one iron group element and at least one platinum group element.

The invention provides a characterization method of a magnetic change of an antiferromagnetic material under the stress action. The characterization method specifically comprises the following steps:arranging a ferromagnetic material on the surface of the antiferromagnetic material, and coupling the ferromagnetic material with the antiferromagnetic material; and providing stress for the antiferromagnetic material, wherein the magnetic property of the antiferromagnetic material change under the stress action, and the magnetic property of the ferromagnetic material also change due to the coupling action, so that the magnetic change of the antiferromagnetic material under the stress action is inducted by measuring the change of the magnetic property of the ferromagnetic material. The characterization method can be used to obtain a magnetic property change rule of the antiferromagnetic material under the stress action, and the magnetic property regulation of the antiferromagnetic materialcan be realized by regulating the stress accordingly. The invention also provides a characterization device which is of a multilayer film structure in turn comprising a substrate layer, an antiferromagnetic material layer, a ferromagnetic material layer and a protective layer, and the characterization device has the advantages of simple structure and convenience in characterization.

An optical sensor is disclosed. The optical sensor may include a substrate, a topological insulator layer formed on the substrate, an oxide layer formed on the topological insulator layer, a graphene layer stacked on the oxide layer, and a dielectric layer covering the graphene layer.

A magnetoelectric composition of boron and chromia is provided. The boron and chromia alloy can contain boron doping of 1%-10% in place of the oxygen in the chromia. The boron-doped chromia exhibits an increased critical temperature while maintaining magnetoelectric characteristics. The composition can be fabricated by depositing chromia in the presence of borane. The boron substitutes oxygen in the chromia, enhancing the exchange energy and thereby increasing Neel temperature.

An antiferromagnetic half-metallic semiconductor of the present invention is manufactured by adding to a semiconductor two or more types of magnetic elements including a magnetic element with a d-electron number of less than five and a magnetic element with a d-electron number of more than five, and substituting a part of elements of the semiconductor with the two or more types of magnetic elements.

Oxidatively-stable, magnetic cobalt nanoparticles and other Group VIII nanoparticles are provided, and production methods. Poly(styrene-b-4-vinylphenoxyphthalonitrile) (a novel composition) or random graft copolymers containing phthalonitrile groups in the backbone are examples of compositions that may be complexed with cobalt or other Group VIII metals.

The invention relates to a binuclear metal organic complex based on nickel (II), the binuclear metal organic complex is a nickel metal organic complex with a repeating unit of [Ni2 (fdc) 2 (bipy) 2 (H2O)4].(H2O) 2, fdc in the [Ni2 (fdc) 2 (bipy) 2 (H2O)4].(H2O) 2 is furan-2, 5-dicarboxylic acid, and dmbpy is 3, 3 '-dimethyl-4, 4 '-dipyridine; the binuclear metal organic complex based on nickel (II) has good antiferromagnetism.

A single-crystal transparent ferromagnetic compound that transmits light and has significant ferromagnetic properties is selected from the group consisting of alkaline earth chalcogenides, alkali chalcogenides, I-VII compounds, II-VI compounds, III-V compounds, IV-VI₂ compounds, IV-IV compounds, and II-VII₂ compounds. At least one element having an incomplete outermost p-electron shell, such as B, C, N, O, F, Si, or Ge, is dissolved in the compound so that the compound has a ferromagnetic transition temperature of room temperature or higher. The ferromagnetic properties of the compound are controlled by adjustment of the concentration of the element having an incomplete outermost p-electron shell and valence electron control through, for example, the addition of an acceptor and a donor.

A permanent magnet comprises a hard magnetic material that contains at least a rare earth element and an anti-ferromagnetic material, wherein the hard magnetic material and the anti-ferromagnetic material are magnetically coupled. A volume ratio of the anti-ferromagnetic material is 20% or less, based on the permanent magnet.

The invention belongs to the field of functional materials, and particularly relates to a coordination balance cationic salt, and a magnet formed by a metal dithiolene complex and preparation methods thereof. The coordination balance cationic salt reacts with coordination anions to obtain the metal dithiolene complex; on one hand, the 4-iodobenzyl and 4-phenylpyridin in the coordination balance cation are respectively of a plane structure, the plane structures respectively have a symmetric axis, and are crossed at the connected carbon atom of 4-iodobenzyl and 4-phenylpyridin, and the whole inverted Y-shaped structure is formed; on the other hand, the coordination anion is of a plane structure, and the self-rotation density of the unpaired electrons is distributed on the whole anion skeleton. By adopting the structure, the magnet formed by the coordination balance cations and coordination anions is of an equal-spacing arrangement structure, the cations and anions are stacked into columns by lines, and the electron transmission and self-rotation coupling of the metal dithiolene complex are favorably performed. The magnet formed by the metal dithiolene complex has the advantages that the technology is simple, the control is easy, the reaction speed is quick, and the product purity is high.

Disclosed is a ferromagnetic group IV-based semiconductor or a ferromagnetic group III-V-based or group II-VI-based compound semiconductor, comprising a group IV-based semiconductor or a group III-V-based or group II-VI-based compound semiconductor, which contains at least one rare-earth metal element selected from the group consisting of Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu. The ferromagnetic characteristic of the ferromagnetic semiconductor is controlled by adjusting the concentration of the rare-earth metal element, combining two or more of the rare-earth metal elements or adding a p-type or n-type dopant.

Disclosed is a ferromagnetic alkali chalcogen compound capable of providing a completely-spin-polarized transparent ferromagnetic material using an alkali chalcogen compound having light-transparency, and a method of adjusting ferromagnetic properties thereof. The transparent ferromagnetic alkali chalcogenide comprises an alkali chalcogen compound which has an anti-fluorite structure and contains at least one metal element selected from a 3d transition metal element group consisting of Ti, V, Cr, Mn, Fe, Co, Ni and Cu; a 4d transition metal element group consisting of Zr, Nb, Mo, Tc, Ru and Rh; a 5d transition metal element group consisting of Hf, Ta, W, Os, Re and Ir; and a lanthanum-series rare-earth element group consisting of Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The selected metal element is incorporated in the alkali chalcogen compound in the form of a solid solution to provide a ferromagnetic characteristic thereto. The ferromagnetic properties are adjusted through control of valence states based, for example, on adjustment of a concentration of each of the metal elements, selection of a combination of two or more of the metal elements, and/or addition of an acceptor and a donor.

The present invention concerns, in particular, a method for obtaining a product with magnetocaloric effect from a single piece of material having a magnetic phase transition, the method comprising irradiation of at least one part of the material with ions, the irradiation being carried out with a suitable flux so that, after the irradiation, the material has various magnetic phase transition temperatures in the various parts of the material.

The invention discloses a method for regulating and controlling magnetic moment arrangement of an antiferromagnetic film material, which belongs to the technical field of information storage and sensing. The method comprises the following steps: pre-stretching treatment, surface polishing and surface argon ion bombardment treatment are carried out on an titanium-nickel-niobium TiNiNb shape memoryalloy substrate; then, a tantalum Ta/ferronickel NiFe/ferro-manganese FeMn/tantalum Ta multilayer film is deposited on the TiNiNb memory alloy substrate; and after the deposition is finished, heat treatment is carried out in a vacuum environment and simultaneously a magnetic field is applied, and finally cooling is carried out to room temperature. The principle is as follows: a remarkable latticestrain is generated through inverse martensite phase transformation of the temperature control TiNiNb substrate and acts on the multilayer film, and an exchange spring structure at a NiFe/FeMn interface can be controlled through the strain, so that the Neel vector rotation of FeMn is caused, and the magnetic moment arrangement of FeMn is effectively regulated and controlled. According to the invention, the structure of an exchange spring can be adjusted through simple temperature control, so that effective regulation and control of FeMn magnetic moment arrangement are realized, and the methodhas the advantages of simple preparation, convenient control, low energy consumption, high efficiency, low cost and the like.