58 results about "Ferromagnetic semiconductor" patented technology

Disclosed is a new type of magnetoresistive random-access memory (MRAM) device using a magnetic semiconductor, which is capable of achieving high-integration and energy saving in a simplified structure without any MOS transistor, based on a rectification effect derived from a p-i-n type low-resistance tunneling-magnetoresistance-effect (low-resistance TMR) diode with a structure having a p-type half-metallic ferromagnetic semiconductor, an n-type half-metallic ferromagnetic semiconductor and at least one atomic layer of nonmagnetic insulator interposed therebetween, or a rectification effect derived from a p-n type low-resistance tunneling-magnetoresistance-effect (low-resistance TMR) diode with a structure devoid of the interposed atomic layer of nonmagnetic insulator.

An exemplary optical isolator, such as a magnetic-semiconductor composite optical isolator, and method for making the same, is provided that includes a semiconductor waveguide and a magnetic-semiconductor composite layer. The semiconductor waveguide includes a guide layer, a first clad layer and a second clad layer. The guide layer includes one or more layers with a first end, a second end, a top, and a bottom, the guide layer allows a light wave incident the first end of the guide layer to propagate in a positive propagation direction, and allows a light wave incident the second end of the guide layer to propagate in a negative propagation direction. The first clad layer and the second clad layer are provided, respectively, relative to the bottom and the top of the guide layer, and the second clad layer has a thickness to allow an optical field penetration through the second clad layer. The magnetic-semiconductor composite layer is provided in the presence of a magnetic field oriented in a desired direction and is positioned relative the second clad layer and at a thickness and index of refraction to receive the optical field penetration through the second clad layer and to attenuate a light wave that propagates in the negative propagation direction more than the attenuation of a light wave that propagates in the positive propagation direction. The magnetic-semiconductor composite optical isolator may be integrated with a semiconductor laser, such as on the same semiconductor substrate.

A spin transistor conducive to the miniaturization and large scale integration of devices, because a magnetization direction of a source and a drain is determined by a direction of the epitaxial growth of a ferromagnet. The spin transistor includes a semiconductor substrate having a channel layer formed thereinside; ferromagnetic source and drain epitaxially grown on the semiconductor substrate and magnetized in a longitudinal direction of the channel layer due to magnetocrystalline anisotropy—the source and drain being disposed spaced apart from each other in a channel direction and magnetized in the same direction—; and a gate disposed between the source and the drain to be insulated with the semiconductor substrate and formed on the semiconductor substrate to control the spin of electrons that are passed through the channel layer.

A 3 group-5 group compound ferromagnetic semiconductor, comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P, wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase as a whole. The ferromagnetic semiconductor can be fabricated by a plasma-enhance molecular beam epitaxy growing method and since it shows the ferromagnetic characteristics at a room temperature, it can be applied as various spin electron devices.

The invention relates to a method for preparing porous titanium dioxide based on light assistance in the technical field of electromagnetic semiconductors, which prepares the porous titanium dioxide by irradiating aqueous solution of titanium glycol salt with ultraviolet light. The method for preparing the porous titanium dioxide is quick and controllable, has good repeatability, and is suitable for large-scale production. The prepared porous titanium dioxide has the characteristics of high specific area, large pore volume, uniform distribution of pore sizes and the like. More important, the porous titanium dioxide can efficiently convert light energy into stored electrons, and the stored electrons not only can provide an electron source for reduction reactions, but also can provide a spinning source to obtain new room temperature ferromagnetic semiconductors.

The invention relates to a single crystal germanium manganese magnetic semiconductor/germanium magnetic heterodiode and a preparation method thereof, which belong to the technical field of spinning electronic devices of an information technology. A p-type layer of the heterodiode is a single Ge1-xMnx ferromagnetic semiconductor, the mol percentage content x of manganese is more than 0 and is less than 15 percent; a Ge layer is a commercial intrinsic single crystal semiconductor Ge or an n-type single crystal semiconductor Ge doped with trace Sb, rectification characteristic under room temperature is adjusted and controlled by using a magnetic field, a magnetic resistor has an extreme value near Curie temperature of the Ge1-xMnx, and the preparation process is matched with the preparation process of a silicon semiconductor. The single crystal germanium manganese magnetic semiconductor/germanium magnetic heterodiode is prepared in such a way that molecular-beam epitaxy epitaxially grows a germanium manganese magnetic semiconductor on a single germanium substrate. Meanwhile, the single crystal germanium manganese magnetic semiconductor/germanium magnetic heterodiode prepared by the method can be better matched with the process of the modern silicon semiconductor, thereby having better application prospect on the aspect of the spinning electronic devices.

This invention provides a preparation method for TiO2 film doped with Co for a room temperature ferro-magnetic semiconductor, which applies a sol-gel method to prepare Co doped TiO2 sol and coats the sol on a substrate of a monocrystal silicon to form a CoxTi1-xO2 film to be annealed and crystallized directly under the vacuum to have the ferromagnetic property, in which, said film does not have the property of room temperature in air, it must be annealed secondly in vacuum or He atmosphere.

Single crystal and polycrystal oxoruthenates having the generalized compositions (Ba_z,Sr_1-z)Fe_xCo_yRu_6−(x+y)O₁₁ (1≦(x+y)≦5; 0≦z≦1) and (Ba,Sr)M_2±xRu_4∓xO₁₁ (M=Fe,Co) belong to a novel class of ferromagnetic semiconductors with applications in spin-based field effect transistors, spin-based light emitting diodes, and magnetic random access memories.

The preparation process of ferromagnetic semiconductor with graded components includes the first step of selecting semiconductor monocrystalline chip as substrate material; the second step of heatingthe substrate material; the third step of growing magnetic semiconductor material with graded components on the substrate; and the fourth step of heat treatment of the magnetic semiconductor material.

The invention belongs to the technical field of semiconductors and discloses a room-temperature transparent ferromagnetic semiconductor material and a preparation method thereof. The room-temperature transparent ferromagnetic semiconductor material is prepared through a technical scheme of preparing novel ferromagnetic semiconductor materials by adding semiconductor functional elements on the basis of amorphous materials with built-in room-temperature magnetism. In an embodiment, the room-temperature transparent ferromagnetic semiconductor material is prepared through magnetron sputtering, the components of the obtained semiconductor materials are Cox(BaFebTac)yO100-x-y, wherein the x and the y are atomic percentages, and the value ranges are that 10<=x<=40, 19<=y<=55, a>b>c and cy>=3. The room-temperature transparent ferromagnetic semiconductor material is a direct band-gap semiconductor with an optical band gap of -3.6 eV and a Curie temperature higher than the room temperature and integrates optical, electrical and magnetic characters; the preparation process is simple; the room-temperature transparent ferromagnetic semiconductor material is an outstanding alternative material applicable to magneto-optical, photoelectric and room-temperature controllable electronic self-spinning devices such as self-spinning effect transistors and self-spinning light emitting diodes.

The invention provides a room temperature ferromagnetic semiconductor material MnSiP2 and a preparation method and applications thereof. The MnSiP2 magnetic semiconductor material belongs to the tetragonal system, I-42d space group, and cell parameters are: a=5.5823(3), b=3.4388(6) Angstrom, c=10.2297(13) Angstrom and z=4. The preparation method comprises following steps: (1) Mn, Si and P are grinded uniformly and placed in a quartz tube and then the tube is vacuumed and sealed and fired; (2) periodic heating is adopted on the quartz tube and then the quartz tube is slowly cooled to room temperature; (3) blocks having good crystallization is taken out, cleaned and dried to obtain the room temperature ferromagnetic semiconductor material MnSiP2. The MnSiP2 magnetic semiconductor material having the chalcopyrite structure is prepared for the first time in the invention, the Curie temperature of the material is 290K; the material can be applied to prepare spin field effect transistors, spin light emitting diodes, spin resonance magnetic tunnel junctions, optical isolators, magnetic sensors, or nonvolatile memory.

Embodiments of the invention provide a polarization rotator. The polarization rotator may be integrated with a waveguide on a substrate, and may include a ferromagnetic semiconductor layer on the substrate, a first doped layer on the ferromagnetic semiconductor layer, and a second doped layer on the first doped layer.

The invention discloses a transfer method and application of a ferromagnetic semiconductor film. The method realizes transfer of a (Ga, Mn) As film on a random substrate. The transferred (Ga, Mn) As film and two-dimensional layered materials (semi-metal graphene, a semiconductor MoS2, and a superconductor NbSe2) of other different physical characteristics establish a magnetic heterostructure through a van der Waals force, and can be used for preparing novel self-spinning devices. By employing the method and application, the compatibility of the (Ga, Mn) As film with the conventional silicon process integration technology can be improved, and an important significance is attached to the application of extension of self-spinning electronics.

The invention provides a ferromagnetic semiconductor, which has the chemical formula LaCu3Fe2Os2O12 and the space group Pn-3, that lattice constant is shown in the description the Curie temperature is520K, and the band gap width is about 0.2 eV. The invention also provides a method for preparing the ferromagnetic semiconductor, comprising: (1) grinding and mixing La2O3, Fe2O3, CuO, Os and an oxygen source to obtain a mixture; 2, fill that mixture into a gold capsule or a platinum capsule and sealing; (3) treating the gold capsule or the platinum capsule under the pressure of 6-10GPa and the temperature of 1000-1200 DEG C; And (4) cooling the reaction product obtained in the step (3) to room temperature, relieving pressure, taking out from the gold capsule or the platinum capsule, grindingand cleaning to obtain a ferromagnetic semiconductor LaCu3Fe2Os2O12. The ferromagnetic semiconductor LaCu3Fe2Os2O12 of the present invention has potential value in the future magnetic semiconductor integrated circuit device, infrared-far-infrared sensors and multifunctional integrated devices.

Ferromagnetic semiconductor-based compositions, systems and methods that enable studies of the dynamics and magnetoresistance of individual magnetic domain walls, and which provide enhanced magnetic switching effects relative to metallic ferromagnets. Aspects of the present invention are enabled by recent studies of the Giant Planar Hall effect (GPHE), and in particular GPHE in (Ga,Mn)As—based devices. The GPHE generally originates from macro- and micromagnetic phenomena involving single domain reversals. The GPHE-induced resistance change in multiterminal, micron-scale structures patterned from (Ga,Mn)As can be as large as about 100Ω, four orders of magnitude greater than analogous effects previously observed in metallic ferromagnets. Accordingly, recent data provide sufficient resolution to enable real-time observations of the nucleation and field-induced propagation of individual magnetic domain walls within such monocrystalline devices. The magnitude of the GPHE is generally size-independent down to the submicron scale indicating that for applications involving nanostructures it is capable of sensitivity comparable to SQUID-based techniques.

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.

The invention provides a ferromagnetic semiconductor material. The chemical formula of the ferromagnetic semiconductor material is (Sr<1-y>Na<y>)(Zn<1-x>Mn<x>)2As2, wherein y is more than 0.1 and less than 0.4, and x is more than 0.05 and less than 0.3. The invention also provides a method for preparing the ferromagnetic semiconductor material, a precursor is sintered in an oxygen-isolated environment by using a solid-phase reaction method to form the (Sr<1-y>Na<y>)(Zn<1-x>Mn<x>)2As2, y is more than 0.1 and less than 0.4, x is more than 0.05 and less than 0.3, and the sintering temperature adopted by the solid-phase reaction method is 670-1,000 DEG C.

The invention provides a single crystal growth method for a ferromagnetic semiconductor material. The ferromagnetic semiconductor material has a chemical formula of (Ba<1-x>K<x>)(Zn<1-y>Mn<y>)<2>As<2>, wherein x is more than 0 and less than 0.5, and y is more than 0 and less than 0.5. The single crystal growth method comprises a step of growing single crystals by using a flux process under heatingconditions, wherein fluxes used in the method are ZnAs and MnAs. The method of the invention is capable of growing large-size high-quality (Ba,K) (Zn,Mn)<2>As<2> single crystals, which is of important significance to research on the physical mechanisms of the crystal and practical application of the crystal in the future.

The present invention provides a ferromagnetic semiconductor material having the formula of Liy (Cd1-xMnx) P, wherein y is greater than 0.6 and less than 1.4, and x is greater than 0 and less than 0.4. The present invention also provides a preparation method of the ferromagnetic semiconductor material, the Liy (Cd1-xMnx) P is prepared by sintering a precursor in an oxygen-isolated environment by solid phase reaction method, wherein y is greater than 0.6 and less than 1.4, x is greater than 0 and less than 0.4, and the sintering temperature is 550-950 DEG C.