80 results about "Ferrimagnetism" patented technology

In a CPP element using a metal intermediate layer excellent in shot noise and response to high frequencies unlike a TMR element, its magnetoresistive effect film includes a magnetic layer mainly made of a half-metal exhibiting ferromagnetism, ferrimagnetism or antiferromagnetism, and largely variable in way of conduction in response to spin direction of electrons.

The present invention is directed to a composite including a substrate and a film deposited on a surface of the substrate, and processes for producing the composites. The deposited film includes at least one metal oxide having the formula: M_xO_y, wherein M is a first, second, or third row transition metal, x is a positive integer from 1 to 7. The film is ferromagnetic, ferrimagnetic, or both ferromagnetic and ferrimagnetic at temperatures greater than 0° C. and has a zero field magnetization of 0.001 emu/g or greater at a temperature of 26.85° C. (300 K). Composites of the present invention may be used, for example, as electrodes in electrochemical devices.

Methods for spatially resolved spin resonance detection in a sample of material, with a resolution as small as 0.5 μ m –1 mm. In one embodiment, a coupler having at least one pair of degenerate orthogonal modes provides an evanescent input signal along one coupler axis to the sample, to which a magnetic field is applied, and senses a spin interaction signal along another coupler axis. In another embodiment, an evanescent input signal is applied to the sample along one of two identical transmission line resonators, and a difference of the two resonator signals provides a spin interaction signal. In another embodiment, a polarized laser beam provides an evanescent input signal to the sample, and the spin interaction signal is sensed according to a second beam polarization direction. Certain ferromagnetic or ferrimagnetic molecules, such as YIG, can be used to tag selected chemical and biological molecules, using spatially resolved spin resonance detection for interrogation.

The invention belongs to the preparation field of magnetic materials, comprising the following steps: firstly, adding the metal ion salt to organic polar solvent for complete dissolution, and then adding solid alkali metal salt and surfactant; the composed mixed solution is reacted at 140-200 DEG C so as to get ferrimagnetic hollow microspheres; the mass ratio between the surfactant and the organic polar solvent is 0.02-0.2:1; the concentration of the metal ion solution is 0.025-0.625mol / L; the molar ratio between the alkali metal salt and the metal ions is 5-20:1; the metal ion is selected from one or more among the iron, cobalt, nickel, manganese, zinc and magnesium ions; the surfactant can be polyethylene glycol series or tween series; the organic polar solvent can be glycol, ethanol, diethylene glycol, triethylene glycol, tetraethylene glycol or glycerol. The method of the invention is simple and the raw materials are cheap and can be easily obtained; the method has good process repeatability, high yield, safety, low cost and wide applicability, which generates no toxic substances and pollutants.

Spinel-type ferrimagnetic particles having a composition represented by the formula:

(MO).n/2(Fe₂O₃)

wherein M is a divalent metal; and n is a molar ratio of Fe to M (n=Fe/M) which is from more than 2.05 to less than 2.5 (2.05<n<2.5), containing a superparamagnetic component in an amount of not more than 2% by mass, and having an average particle diameter of 5 to 30 nm, said spinel-type ferrimagnetic particles being respectively coated on surface thereof with a hydroxide of at least one metal selected from the group consisting of Si, Al, P and Zn in an amount of not more than 10% by mass, calculated as the metal, as well as a magnetic recording medium containing the spinel-type ferrimagnetic particles. The spinel-type ferrimagnetic particles can exhibit a high coercive force irrespective of fine particles, and are excellent in dispersibility and chemical stability, as well as the magnetic recording medium for high-density recording can exhibit not only excellent frequency characteristics and high output characteristics, but also an excellent weather resistance and a high reliability.

The method includes following steps: using chemical coprecipitation method to prepare mixed liquor of ammonia (or sodium hydroxide), bivalent iron salt (manganese, nickel, cobalt etc.) and tervalent iron salt; dropping the mixed liquor to ion exchange water, and keeping pH of solution at 7; mixing round the solution to generate suspending liquid of ferrite; using ultrasonic to coat a layer of surface active agent on surfaces of fine grains evenly; finally, using ultrasonic to disperse fine grains on solvent evenly.

Novel metal oxide compositions are disclosed. These ferromagnetic or ferrimagnetic compositions have resitivities that vary between those of semiconducting and insulating materials, and they further exhibit Curie temperatures greater than room temperature (i.e., greater than 300 K). They are perovskite structures with the general chemical formulas (A_1-xM_x)BO₃, (A_1-xM_x)(B′B″)O₃ or A(B_1-xM_x)O₃, where A can be a 1⁺, 2⁺ and 3⁺ charged ion; B can be a 5⁺, 4⁺, 3⁺ charged ion; B′ and B″ can be 2⁺, 3⁺, 4⁺, 5⁺ and 6⁺ charged ion. M is a magnetic ion dopant. X-ray diffraction patterns are presented for exemplary compositions.

The invention relates to a method for preparing gamma-Fe2O3 nanometer wire filling carbon nitrogen multi-wall nanometer tubes through one-step reaction. Particularly, the invention belongs to a method for preparing metal oxide nanometer wire filling carbon nitrogen nanometer tubes under the condition of the existence of FeNi (50 percent of Fe and 50 percent of Ni in mass percent) catalyst thin films in the plasma body chemical gas phase deposition process of paraffin gas (preferably methane), air and hydrogen (according to a flow rate ratio of 80/10/20 with the unit of ml/minute in a standard state). The products prepared by the invention have good orientation effect and high yield. The single crystal nanometer wires filled to the inside have ferrimagnetism, and the multi-wall tubular structures at the outer layer have the special nitrogen doped bamboo joint type structures. The invention has the advantages of simple method, one-step completion, easy control and convenient industrial production. The prepared magnetic nanometer materials have wide application prospects in the fields of biological medicine, field generation devices, catalytic materials and the like.

Systems and methods that facilitate magnetic collection and/or manipulation of individual micropallets are provided. The embodiments provided herein are directed to a new method for collecting micropallets once released from a substrate. It is accomplished by endowing the micropallets with magnetic properties by incorporating ferromagnetic or superparamagnetic nanoparticles into the photoresist material or otherwise incorporating magnetically responsive material into the micropallet structure. The magnetic particles, which posses magnetic qualities, e.g., ferromagnetism, ferrimagnetism, paramagnetism, and are composed of iron, nickel, and/or other magnetic materials, are mixed into the bulk photoresist prior to its use in the fabrication of microstructures. Also covered are other methods of incorporating magnetically-attractable material into the micropallet structure, such as plating of the micropallets with a material that is magnetically responsive, such as nickel. Additionally, the embodiments provided include a “collection probe” that is used to collect the released magnetic micropallets.

A perpendicular magnetic recording medium including a substrate, a soft-magnetic backing layer formed on the substrate, a magnetic recording layer having perpendicular magnetic anisotropy formed on the backing layer, and a leakage magnetic field control layer having ferrimagnetism formed on the magnetic recording layer. The leakage magnetic field control layer is exchange-coupled to the magnetic recording layer antiferromagnetically or ferrimagnetically to thereby suppress the influence of leakage magnetic fields from the backing layer and the magnetic recording layer and reduce the medium noise.

The invention provides a laminated magnetic bead with large high-frequency impedance. A lamination body is in a structure formed by laminating at least two types of insulator thin sheets as a whole body; one type is a first insulator thin sheet which is made of a ferrimagnetism material and used for forming upper and lower substrates of the lamination body; and the other type is a second insulator thin sheet which is close to an internal electrode and is used for forming the lamination body; the main body of the lamination body is provided with a plurality of first insulators made of the ferrimagnetism material and at least one layer of a second insulator which is arranged at a specific position inside a first insulating layer and is made of a material with low dielectric constant and low consumption; and a coil conductor of a coil layer is arranged in each first insulator; and the dielectric constant and the consumption of the entire material of the laminated magnetic bead can be reduced by adjusting a layer quantity and the thickness of the second insulator, namely the stray capacitance is reduced, so that the high-frequency impedance of the laminated magnetic bead can be increased. Furthermore, a series of the laminated magnetic beads with the different high-frequency impedances can be obtained by only using one kind of ferrite slurry. Compared with the design of the traditional various ferrite materials, the cost can be greatly reduced.

The invention relates to a single-phase multiferroic barium ferrite ceramic material and a preparation method thereof. The preparation method comprises the following steps: weighing barium salt and ferric salt, forming a barium precursor solution and a ferric precursor solution, weighing polyethylene glycol, and dissolving the polyethylene glycol in deionized water for later use; mixing the precursor solutions, adding a mixed solution of ammonia water and polyethylene glycol, and mixing to obtain a suspension; centrifugalizing, pouring out the supernatant, washing the centrifugalized precipitate, calcining, and removing organic substances to obtain initial powder; and grinding, tabletting, and sintering at high temperature to obtain the target product. The barium ferrite ceramic material has multiferroic performance, and has excellent ferroelectricity and ferrimagnetism at room temperature; and the average particle size is 2 mu m or so, and, the particle distribution is uniform. The barium ferrite ceramic material has excellent ferroelectricity, ferrimagnetism and obvious multiferroic performance, and thus, is a practicable multiferroic material. In addition, the invention has the advantages of simple preparation technique, low facility request, accessible raw materials, low price and the like.

The invention discloses a low-loss FeSiAl/MnZn ferrite soft magnetic composite magnetic powder core with stable magnetic conductivity and a preparation method of the low-loss FeSiAl/MnZn ferrite soft magnetic composite magnetic powder core with stable magnetic conductivity. The raw materials of the magnetic powder core comprise an adhesive, a lubricant and FeSiAl/MnZn ferrite composite magnetic powder; the FeSiAl/MnZn ferrite composite magnetic powder comprises phosphatized FeSiAl magnetic powder and a MnZn ferrite layer, and the surface of the phosphatized FeSiAl magnetic powder is coated with the MnZn ferrite layer through ball milling. According to the preparation method, a phosphoric acid/MnZn ferrite composite coating process is mainly adopted, and MnZn ferrite coating is carried out on the phosphorized FeSiAl powder through the high-energy ball milling method. The preparation method has the advantages of convenience in material preparation, simple operation, uniform coating and good coating effect, and can better facilitate industrial popularization; the MnZn ferrite with ferrimagnetism serves as an insulating coating agent, so that the magnetic dilution phenomenon caused by a non-magnetic substance serving as the coating agent is reduced. The high-frequency performance of the FeSiAl magnetic powder core can be improved, and the provided FeSiAl/MnZn ferrite soft magnetic composite magnetic powder core is low in loss and stable in magnetic conductivity under high frequency.

A composite magnetic material includes a soft magnetic phase including a magnetic material containing a ferromagnetic material including Fe or Co as a main component and a plurality of hard magnetic particles present and dispersed in a form of islands in the soft magnetic phase. The hard magnetic particles have an average particle size of 2 nm or more and include a magnetic material containing a ferrimagnetic material or an antiferromagnetic material as a main component while they are present with an average inter-particle distance of 100 nm or less in the soft magnetic phase. The composite magnetic material has excellent magnetic properties and can be made into a lightweight magnet to be used e.g. in a motor of an aircraft.

The invention relates to a preparation method of a porous recyclable ferromagnetic ferrite/titanium dioxide (TiO2) photocatalysis composite material. The material takes an active carbon template and apore-forming agent and is prepared through modification, magnetic medium filling, titanium dioxide loading and template removal, and has the advantages of high photocatalysis efficiency and good magnetic separation efficiency. The preparation method comprises the following steps: 1) nitric acid backflow modification of active carbon; 2) a solvothermal method is employed for appropriate filling ofa ferrite magnetic medium on the modified active carbon to obtain a ferrite/active carbon composite material having magnetic responsiveness; 3) an immersion method is employed for loading TiO2 nano particles by taking butyl titanate as a precursor to obtain a TiO2/ferrite/active carbon composite material; and 4) the TiO2/ferrite/active carbon composite material is calcined in air to obtain the porous recyclable ferromagnetic ferrite/titanium dioxide photocatalysis composite material with easy magnetic separation. The titanium dioxide photocatalysis composite material has the advantages of simple preparation technology, cycle utilization, and high catalysis efficiency.