30results about How to "Decreasing remanence" patented technology

A PMR writer is disclosed that minimizes pole erasure during non-writing and maximize write field during writing through an AFM-FM phase change material that is in an AFM state during non-writing and switches to a FM state by heating during writing. The main pole layer including the write pole may be comprised of a laminated structure having a plurality of “n” ferromagnetic layers and “n−1” AFM-FM phase change material layers arranged in an alternating manner. The AFM-FM phase change material is preferably a FeRh or FeRhX alloy (X=Pt, Pd, or Ir) having a Rh content >35 atomic %. AFM-FM phase change material may also be used as a flux gate to prevent yoke flux from leaking into the write pole tip. Heating for the AFM to FM transition is provided by write coils and / or a coil located near the AFM-FM phase change material to enable faster transition times.

A rare earth permanent magnet is prepared by disposing a powdered metal alloy containing at least 70 vol % of an intermetallic compound phase on a sintered body of R—Fe—B system, and heating the sintered body having the powder disposed on its surface below the sintering temperature of the sintered body in vacuum or in an inert gas for diffusion treatment. The advantages include efficient productivity, excellent magnetic performance, a minimal or zero amount of Tb or Dy used, an increased coercive force, and a minimized decline of remanence.

A method for producing a sintered R-T-B based magnet includes the steps of: providing R-T-B based alloy powders A and B so that the R-T-B based alloy powder B has a particle size D50 that is smaller by at least 1.0 μm than that of the R-T-B based alloy powder A and that there is a difference ΔRH of at least 4 mass % between the higher content of a heavy rare-earth element RH in the R-T-B based alloy powder B and the lower content of the heavy rare-earth element RH in the R-T-B based alloy powder A; mixing these two R-T-B based alloy powders A and B together; compacting the mixed R-T-B based alloy powder to obtain a compact with a predetermined shape; and sintering the compact.

The present invention provides a method for preparing a rare earth permanent magnet material. The preparation method of the present invention comprises atomizing spray process and infiltrating process, wherein the atomizing-sprayed sintered rare earth magnet is placed in a closed container before infiltrating. Through the atomizing spray process a solution containing a heavy rare earth element is coated on the surface of a sintered R1-Fe(Co)—B-A-X-M rare earth magnet, and after baking, heat treatment is performed to infiltrate the sprayed heavy rare earth element to the grain boundary phase of the sintered rare earth magnet. This method decreases the amount of a heavy rare earth element used, increases the coercive force of magnets with a little decrease of remanence, decreases the remanence temperature coefficient and coercive force temperature coefficient of the magnet, and improves resistance of the magnet against demagnetization at a high temperature.

A material for anisotropic magnet, comprising,(1) a Pr-T-B—Ga-based composition containing Pr: 12.5 to 15.0 atomic percent, B: 4.5 to 6.5 atomic percent, Ga: 0.1 to 0.7 atomic percent, and the balance of T and inevitable impurities, wherein T is Fe or obtained by substituting Co for a portion of the Fe; and having,(2) a degree of magnetic alignment of 0.92 or more, wherein the degree of magnetic alignment is defined by remanence (Br) / saturation magnetization (Js); and(3) a crystal grain diameter of 1 μm or less.