248 results about "Magnetic semiconductor" patented technology

A nonmagnetic semiconductor device which may be utilized as a spin resonant tunnel diode (spin RTD) and spin transistor, in which low applied voltages and/or magnetic fields are used to control the characteristics of spin-polarized current flow. The nonmagnetic semiconductor device exploits the properties of bulk inversion asymmetry (BIA) in (110)-oriented quantum wells. The nonmagnetic semiconductor device may also be used as a nonmagnetic semiconductor spin valve and a magnetic field sensor. The spin transistor and spin valve may be applied to low-power and/or high-density and/or high-speed logic technologies. The magnetic field sensor may be applied to high-speed hard disk read heads. The spin RTD of the present invention would be useful for a plurality of semiconductor spintronic devices for spin injection and/or spin detection.

A three terminal magnetoresistance head capable of providing a high output and a large output current is provided. A MIS junction multilayer film composed of a magnetic semiconductor, a metal magnetic multilayer film, and a tunnel magnetoresistance element is applied to a three terminal magnetoresistance device.

The invention discloses a Co-Ga codoped Zno base diluted magnetic semiconductor film, wherein a Co molar content is more or equal than 2and less or equal to 10, a Ga molar content is more or equal to 1and less or equal to 3 The diluted magnetic semiconductor film is prepared by a pulsed laser deposition method and a pure ZnO, Co2O3, a Ga2O3 powder mixed sintered ceramic chip is employed as a target material. A substrate is placed in a growth chamber of a pulsed laser deposition device after cleaning the substrate, and the growth chamber is vacuumized to a background vacuum less than 8.0 *10 Pa. The mixture is grown under an O2 atmosphere with a pressure of 2-15Pa and a temperature of 350-700 DEG C. The preparation method of the invention is simple, an n type doping carrier concentration can reach 5.0*10-5.0*10 cm and simultaneously have a room temperature iron magnetic property.

The present invention provides oxide magnetic semiconductor film with adjustable electronic transport properties and manufacture method thereof, which belongs to information technology rotating electron material field. The series oxide magnetic semiconductor film displays common electric transport property: material with low electric resistivity being Mott range transition resistor, material with middle electric resistivity being hard Efros range transition resistor, material with high electric resistivity being hardgap resistor. The super thin iron magneto- metallic layer and the wide forbidden region oxide semiconductor layer are alternating deposited on substrate by using the method of magnetron sputtering or pulsed laser depositing through accurate control partial pressure of oxygen in film preparation process to regulate electric transport property of material. Electric transport property of oxide magnetic semiconductor film is only related to concentration of oxygen vacancy in material.

The invention relates to a detecting method for the magnetic semiconductor carrier mobility, which is used to solve the abnormal Hall Effect of the magnetic semiconductor, the method of detecting movability with the common Hall Effect which is used to detect the non-magnetic semiconductor carrier density and the mobility is not suit for it. According to the literature document, there isn't a method to detect the magnetic semiconductor carrier mobility at present. The invention provides that the electrochemistry C-V method combines with the Van de Pol method (magnetic field is not needed), the magnetic semiconductor carrier mobility is measured by the electrochemistry C-V method, the electrical resistivity is measured by the Van de Pol method, and the magnetic semiconductor carrier mobility is determined according to the relationship of the carrier density, electrical resistivity and the carrier mobility. The invention doesn't relate to the Hall measurement and avoid the influence of Hall Effect. The characteristics of invention are that it needn't the specially-produced equipment, easy to operate and measure accuracy.

A memory cell in a so-called MRAM by utilizing a tunnel magnetic resistance in the prior art has raised problems that a magnetic field to be applied to a TMR element is essentially weak since a word line for write is disposed apart from the TMR element, that a large current is required at the time of a writing operation, and that electric power consumption is large. In order to solve the above-described problems experienced in the prior art, the present invention provides an MRAM memory cell structure and its fabricating method in which a word line for write is disposed near a TMR element and surrounds it in three directions.

The invention discloses (GeTe) a (Sb2Te3) b base dilute magnetic semiconductor material for storing information, which is characterized of doping (GeTe) a (Sb2Te3) b alloy, wherein the percentage composition of doping dose is larger than 0 and is less than 40%, doping element is one of magnetic iron, cobalt, nickel and manganese or rare earth element, or mixture thereof. Under the function of external energy, the invention can realize reversible material between crystalline state and amorphous state. The material can realize the change of resistance value from twice to several magnitude range before and after reversibility; simultaneously, the light reflectivity of the material is different before and after the reversibility; and the material has variable magnetisms before and after the reversibility or the material has a certain different magnetic intensity before and after the reversibility, when a magnetic detector scans, different magnetic signals recorded in the two different regions of amorphous phase and crystal phase can be detected or converted into an electric signal to be detected, are respectively expressed to be 0 and 1, and is applicable to phase change storage, light storage and magnetic storage.

A measuring system for measuring the dichroism of the magneto-optical circular polarization with adjustable measuring geometry is provided, whose structure is that: a femtosecond laser excites the white light of the ultra-continuous spectrum, and divides the light by a monochrometer, which forms a monochromatic light whose wavelength can be adjustable. The monochromatic light can polarize through a purified Glan-Taylor prism with the extinction coefficient of 10 <5>; a lantern fly modulator, whose optical axis is 45degree angled with the optical axis of the Glan-Taylor prism to make the light become the circularly polarized light with the alternative variation of the sinistrality and the dextrorotation; a sample, which is put on the center of the cryogenic magnet; The circularly polarized light focuses on the sample, and the reflex reflected from the sample is focuses on the first LED detector; a phase-locking amplifier, whose reference signal is provided by the lantern fly modulator used for testing the difference of light intensity between the sinistrality and the dextrorotation of the circularly polarized light. The invention can not only test the frequency spectrum of the dichroism of the magneto-optical circular polarization of the materials, magnetic density and temperature dependence, but also can test the magnetocrystalline anisotropy of the magnetic semiconductor.

The present invention provides one low temperature process of preparing RE magnetic semiconductor of Mg-doped nanometer zinc oxide line, and belongs to the field of nanometer material preparing technology. The technological process includes the following steps: cutting silicon wafer into chips with diamond cutter and setting in culture dish; mixing pure zinc powder and manganese chloride powder in the weight ratio of 1:3 to 1:1; reaction in a tubular furnace to obtain the yellow product deposited on the silicon chip; and observing the deposited nanometer line on the silicon chip with a scanning electronic microscope. The present invention is superior in that the prepared Mg-doped nanometer zinc oxide line has diameter of 50 nm, smooth surface, high yield and excellent magnetic performance.

The invention discloses a ZnO-based diluted magnetic semiconductor thin film and a preparation method of the ZnO-based diluted magnetic semiconductor thin film. The analyzed pure metal nitrate is taken as a raw material, and a method 1 comprises the following steps of: obtaining a doped ZnO powder body by a water solution coprecipitation method, sintering by a solid-phase method to obtain a ceramic target material, and preparing into a doped diluted magnetic semiconductor ZnO thin film by a pulsed laser deposition (PLD) method. Or the analyzed pure metal nitrate is taken as a raw material, and a method comprises the step of preparing a doped ZnO-based diluted magnetic semiconductor ZnO thin film through the technological process of preparing sol, spinning and thermally treating by a sol-gel method. The energy gap of the prepared ZnO-based thin film can be adjusted and controlled due to the doping of Mg and Cd, so that the ferromagnetism of the ZnO-base thin film can be adjusted and controlled. The Co-doped or Mn-doped ZnO-based diluted magnetic semiconductor thin film can be co-doped into the Cd, so that band gap can be reduced, and the room-temperature saturation magnetization of the thin film can be enhanced; and the band gap can be enlarged due to the codoping of Mg, so that the room-temperature saturation magnetization of the thin film can be reduced.

The invention discloses an oxide base rare magnetic conductive film and preparing method with indoor temperature magnet in the material scientific domain, which is characterized by the following: displaying the component as LixNi1-x-yMyO (o<=x<=0.1; o C23C 30/00 C23C 18/02 4 5 1 2006/9/1 1924095 2007/3/7 100451172 2009/1/14 2009/1/14 2009/1/14 Tsinghua University Beijing 100084 Lin Yuanhua Nan Cewen Zhao Rongjuan liguang song 11246

The invention provides a method for preparing a Fe-doped ZnO room temperature diluted magnetic semiconductor material, which adopts a coprecipitation method and includes: A. prepare a mixed solution of Fe<3+> and Zn<2+> and a NaOH solution; B. mix the mixed solution of Fe<3+> and Zn<2+> and the NaOH solution to form a precipitate, then filter, separate and wash the precipitate; C. dry, pre-sinter, grind, tablet and sinter the precipitate to obtain the Fe-doped ZnO room temperature diluted magnetic semiconductor material. The invention provides a completely new method for preparing the Fe-doped ZnO room temperature diluted magnetic semiconductor material and the Fe-doped ZnO room temperature diluted magnetic semiconductor material prepared by the method has room temperature ferromagnetism.

The invention discloses an oxide diluted magnetic semiconductor/ferroelectric heterojunction structure which consists of the following three layers: a base layer is a substrate; a middle layer is an oxide diluted magnetic semiconductor film and an upper layer is a ferroelectric film. The substrate is Si, sapphire, SrRuO3 or other perovskite oxide substrates; the oxide diluted magnetic semiconductor film is large energy gap oxide films of ZnO, TiO2 or SnO2 doping with transition metal elements of Mn, Fe, Co, Ni or Cr; the ferroelectric film is films of lead zirconate titanate, Nd-Bi titanate or barium strontium titanate. The invention also discloses two preparation methods of the oxide diluted magnetic semiconductor/ferroelectric heterojunction structure, namely, a pulsed laser deposition method and a sol-gel method. The oxide diluted magnetic semiconductor/ferroelectric heterojunction structure can carry out non-volatile modulation of ferromagnetism under the effect of an applied electric field and can be widely applied to the fields of electronic computers, spin electronics and non-volatile memorizers.

The invention discloses a p type doped CuCro2-based dilute magnetic semiconductor material and a manufacturing method thereof. The CuCro2-based dilute magnetic semiconductor polycrystal block is manufactured, and has a molecular structural formula of CuCr(1-x)TMxO2, wherein, TM is transition metal elements which are Fe, Co, Ni, Mn, and the concentration thereof x is more than or equal to 0 and is less than or equal to 0.2. Cupric acetate, chromic nitrate and transition metal salt are measured according to a mole ratio of cupric, chromic to transition metal of 1: (0.80-1): (0-0.20), the powder is added into distilled water and added with adequate amount of citric acid, and then stirred at room temperature till fully dissolved, thereby obtaining a well mixed solution; then, after processes of parching, grinding, tablet compressing and heat treatment, dilute magnetic semiconductor block material of CuCr(1-x)TMxO2 is manufactured. The invention adopts a sol-gal method and has the advantages of low energy consumption, simple technique and the like. In the invention, all of the components in the solution are well mixed, and the uniformity degree can reach molecular level, so that multi-component homogenous dopant can be manufactured was well as products that are hard to be obtained by traditional solid phase methods. And experiment results have repeatability.

A magnetic switching element includes: a ferromagnetic layer which is substantially pinned in magnetization in one direction; and a magnetic semiconductor layer provided within a range where a magnetic field from the ferromagnetic layer reaches, where the magnetic semiconductor layer changes its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto, and a magnetization corresponding to the magnetization of the ferromagnetic layer is induced in the magnetic semiconductor layer by applying a voltage to the magnetic semiconductor layer.

The invention belongs to the technical field of semiconductor film materials and relates to a rare-earth metal ion doped ZnO diluted magnetic semiconductor film with high quality, low resistivity and intrinsic ferromagnetism and a preparation method thereof. The chemical composition of the film provided by the invention is in accordance with the general chemical formula, namely, Zn1-x-yErxAlyO, wherein x is greater than 0 and less than or equal to 0.03, and y is greater than 0 and less than or equal to 0.02. In the method provided by the invention, a way of rare-earth metal ion Er and Al donor doping is adopted, a ceramic target is utilized as a base and the ZnO-based diluted magnetic semiconductor film with intrinsic ferromagnetism is prepared by adopting an ICP-PVD (inductively coupled plasma-physical vapor deposition) technique. By adopting the ICP-PVD technique in the invention, the metal ion Er can be evenly doped into the ZnO crystal lattice; and meanwhile, the carrier concentration of the ZnO film doped with Al can be obviously improved, thus the ferromagnetic transformation among Er<2+> ions can be effectively adjusted and all films have intrinsic ferromagnetism and anomalous Hall effect above room temperature. Therefore, the semiconductor film provided by the invention can be widely applied to spinning electron devices.

The invention discloses a p-type doped ZnO-based diluted magnetic semiconductor material and the preparation method. The material molecular structure formula is ZnTMyxO, in which Tm represents transition metal element, Co, Ni, Mn and other elements, x=0-10%, y=0-20%. Method is that zinc acetate, sodium acetate and transition metal salt are dissolved in ethylene glycol monomethyl ether as precursor; then ethanol is added as stabilizer; after stirring, the stable sol is formed. After the sol being dried and heat treated, the power sample is obtained; or by spin coating, the sol is coated uniformly on the Si wafer cleaned in advance or other substrates (quartz glass, sapphire, SiC and other materials), after being dried and heat treated, the thin film sample is obtained. The sol-gel method of preparing material has the advantage of simple technology, low cost, and obtaining easily large area thin films; based on the preparation of the room-temperature ferromagnetic ZnO-based diluted magnetic semiconductor, the Na ion is introduced successfully to obtain the p-type doping; therefore the magnetic property is improved, and by regulating concentration of the Na ion, the magnetic property is controlled.

The invention discloses a method for preparing Cd1-xCoxS dilute magnetic semiconductor nanoparticles by a gas-liquid surface reaction, which belongs to the technical field of the preparation of Cd1-xCoxS dilute magnetic semiconductor nanoparticle materials. The gas-liquid surface reaction is carried out in a reaction chamber, a segment-shaped glass table with a spherical surface upward is put at the bottom in the reaction chamber, and the spherical surface is uniformly polished. The method comprises the following steps of: firstly, extracting solution of cadmium acetate, solution of cobalt acetate, solution of polyvinyl pyrrolidone (PVP) and de-ionized water, and uniformly mixing to obtain reaction liquid to be reacted; secondly, performing the gas-liquid surface reaction, introducing H2S gas into the reaction chamber and dropping the reaction liquid to be reacted on the spherical surface of the glass table; and finally, extracting solution after reaction and centrifugally washing with the de-ionized water and ethanol. The Cd1-xCoxS dilute magnetic semiconductor nanoparticles prepared by the method of the invention have high saturated magnetic strength and a uniform grain size.

This invention relates to a method for preparing ZnO base dilution magnetic semiconductors with Sol-Gel method by applying Sol-Gel method combined with doped ferromagnetic ions as Fe. Co or Mn. Ni etc. to prepare ZnO base dilution magnetic semiconductor films. It is first to prepare ZnO Gel solution by dissolving a proportion of analytically pure zinc acetate and metal salt (the atomic concentration ratio of Fe and Zinc is 1-1.5%) in asolute alcohol, mixed evenly to get ZnO colloidal solution finally which is informly coated on the rotating Si chips. The film is kept for a period of time under room temperature-100 deg.C after a few minutes of heat treatment, then to go through heat treatment for 0.5-1.5 hours under nitrogen atmosphere at 500-900 deg.C.