114 results about "Magnetic transitions" patented technology

There are provided a magnetoresistance effect element, a magnetic head, a magnetic head assembly and a magnetic recording system, which have high sensitivity and high reliability. The magnetoresistance effect element has two ferromagnetic layers, a non-magnetic layer provided between the ferromagnetic layers, and a layer containing an oxide or nitride as a principal component, wherein the layer containing the oxide or nitride as the principal component contains a magnetic transition metal element which does not bond to oxygen and nitrogen and which is at least one of Co, Fe and Ni.

The invention relates to a 1,2,4-triazole and 5-sulfonyl m-phthalic acid mixed ligand cobalt (II) coordination compound magnetic material as well as a preparation method and application thereof. The chemical formula of the coordination compound magnetic material is {[Co3.5(H2O)2(trz)4(sip)].1.5H2O}, wherein trz is 1,2,4-triazole monovalent anion; and sip is trivalent anion of 5-sulfonyl m-phthalic acid. The coordination compound magnetic material is prepared by using a solvothermal method and has higher yield and good repeatability. The coordination compound magnetic material is the first case of cobalt (II) compound containing the 1,2,4-triazole and 5-sulfonyl m-phthalic acid mixed ligand, shows a magnetic transition phenomenon induced by a three-step field under different external magnetic fields, can be used as a molecule-based magnetic material and has great application value in the field of material science.

A method of simultaneously forming magnetic transition patterns in both side surfaces of a dual-sided magnetic or magneto-optical (MO) recording medium comprises steps of:

(a) providing a dual-sided magnetic or MO recording medium having first and second opposing side surfaces;

(b) providing a first magnetic stamper/imprinter having a first topographically patterned imprinting surface comprising a plurality of projections and depressions arranged in a first pattern corresponding to a first magnetic transition pattern to be formed in the first side surface;

(c) providing a second magnetic stamper/imprinter having a second topographically patterned imprinting surface comprising a plurality of projections and depressions arranged in a second pattern corresponding to a second magnetic transition pattern to be formed in the second side surface, the second magnetic stamper/imprinter being formed from the first magnetic stamper/imprinter in a “mother”/“son” relationship;

(d) contacting the first side surface with the first topographically patterned imprinting surface of the first magnetic stamper/imprinter;

(e) contacting the second side surface with the second topographically patterned imprinting surface of the second magnetic stamper/imprinter; and

(f) simultaneously forming magnetic transition patterns in both side surfaces of the medium by contact printing.

A bistable electromagnetic microdriver is structurally characterized by that a pair of permanent-magnet bases are symmetrically arranged on a soft-magnetic liner on base, a soft-magnetic torsional beams is arranged via soft-magnetic transition layer on said two bases to form a bridge structure, and a pair of soft-magnetic cantilevers are horizontally and symmetrically extended from the middle part of torsional beam to make their ends above the planar windings containing iron core on said liner. An air gap is between the end of cantilever and planar winding.

A magnetic data storage system having a scanning tip array based system and a shape memory thin film-based data storage medium. Prior to storing data, the medium is in its non-ferromagnetic austenitic phase. Indentation stress locally induces martensitic transformation of the medium, which in turn generates a locally ferromagnetized surface. By measuring the magnetic force interaction between the tip and the medium surface, inscribed magnetic information can be read. The shape memory thin film enables the stress-induced local magnetic transition to provide a fast data storage system with high data storage density.

The invention relates to a preparation method of alloy thin strip magnets of Sm(Co,Cu,Fe,Zr)-z types and relates to a magnet containing hard magnetic materials of a rare-earth metal and magnetic transition metals. The preparation method comprises the following steps: presenting a chemical composition formula in a melt of Sm(Cox Cuy Feu Zrv) z; rapidly quenching the melt on a cooling molybdenum roller or a copper roller rotating at a peripheral speed of 5-40 m/s by a melt rapidly quenching furnace or a vacuum melting rapidly quenching continuous furnace to obtain melt thin strips of Sm(Co,Cu,Fe,Zr)-z types; pulverizing the melt thin strips into powder; pressing the powder into blocks in a magnetic field larger than 1T; and compacting the blocks in a cold isostatic press before final heat treatment. The invention provides three heat treatment processes and accordingly obtains the practical block alloy thin strip magnets of Sm(Co,Cu,Fe,Zr)-z types with different characteristics.

An apparatus for performing contact printing of a magnetic transition pattern in a magnetic recording medium, comprising:

• • (a) a stamper/imprinter including a body formed of at least one magnetic material having a high saturation magnetization B_sat and a high permeability, including an imprinting surface adapted to be placed in intimate contact with a surface of a magnetic layer, the imprinting surface comprised of a plurality of patterned areas which separate a plurality of areas which are not patterned, each of the areas which is not patterned being provided with at least one of:
    • (i) mechanical reinforcing means for preventing deformation of the body when the imprinting surface is urged into contact with the surface of the magnetic layer; and
    • (ii) gas venting means for facilitating removal of air or other gas from between the imprinting surface and the surface of the magnetic layer when the former is urged into contact with the latter.

The invention provides a set of standards for accurately calibrating a vacuum thermogravimetric analyzer (VTGA). The invention solves the problem of calibrating a VTGA by using the actual magnetic transitions and associated transition temperatures, or Curie temperatures, T_C's, of a set of standards which can be used in-situ at the location of the sample holder obviating the difficulties associated with indirect methods of calibration. The set of standards permits accurate calibration through sufficiently numerous calibration points over a rather limited low-temperature range for determining vapor pressures of compounds. The set of temperature calibration standards is fabricated from slugs of ferromagnetic material. The composition of the ferromagnetic material in each slug is altered by alloying a ferromagnetic constituent with a non-ferromagnetic constituent to provide a plurality of standards with different Curie temperature over the limited temperature range. In particular, an embodiment of the invention using alloys of Ni and Cu where the amount of Cu varies between less than 10% up to approximately 50% by weight provides a set of standards that can span temperatures in any selected range from approximately 300 C to −150 C respectively.

The invention provides a preparation method used for Sm(Co, M)7 typed alloy ligature magnet, belonging to the magnet technical field of hard magnetic material containing rare earth metal and magnetic transition metal. The preparation method comprises the steps as follows: the molecular formula of the fuse is SmCo<7-x>Mx(CNT)y; wherein, M is Hf, Ga or Si; CNT is carbon nano-tube; according to the atom percentage, the symbols which limits the composition meets the following formulas: x is not less 0.05 and not more than 1.6; y is not less than 0.01 and not more than 0.1; the fuse is rapidly quenched on a cooling molybdenum roller wheel or a copper roller wheel which rotates at a circumferential velocity of 10-60m/s, thus preparing the Sm(Co, M)7 typed alloy ligature magnet which has the mass magnetization intensity of 40.0-105.0Am<2>/kg, has the intrinsic coercivity of 480.0-1840.0kA/m after being magnetized in an external magnetic field of 4.8MA/m, has the intrinsic coercivity of 480.0-2,000.0kA/m after being magnetized in an external magnetic field of 7.2MA/m, has the thickness of 20-120 microns and has the average grain size of 10-200nm. The carbon nano-tube which is used as an ideal pinning phase stabilizes the phase structure of the Sm(Co, M)7 typed alloy ligature magnet when in a quick quenching state and a heat disposal state, optimizes the micro-structure of the grain size and leads the alloy to be practical permanent magnet with high coercivity.

The invention provides a set of standards for accurately calibrating a vacuum thermogravimetric analyzer (VTGA). The invention solves the problem of calibrating a VTGA by using the actual magnetic transitions and associated transition temperatures, or Curie temperatures, T_C's, of a set of standards which can be used in-situ at the location of the sample holder obviating the difficulties associated with indirect methods of calibration. The set of standards permits accurate calibration through sufficiently numerous calibration points over a rather limited low-temperature range for determining vapor pressures of compounds. The set of temperature calibration standards is fabricated from slugs of ferromagnetic material. The composition of the ferromagnetic material in each slug is altered by alloying a ferromagnetic constituent with a non-ferromagnetic constituent to provide a plurality of standards with different Curie temperature over the limited temperature range. In particular, an embodiment of the invention using alloys of Ni and Cu where the amount of Cu varies between less than 0% up to approximately 50% by weight provides a set of standards that can span temperatures in any selected range from approximately 300 C to −150 C respectively. Prior to use in calibration, each slug is preferably placed in a magnetic field having a magnitude sufficient to provide a well defined magnetic transition at the Curie temperature.