Abstract: A rare earth magnet powder has a chemical composition which includes R: 5 to 20% (wherein, R represents one or two or more rare earth elements being inclusive of Y but exclusive of Dy and Tb), one or two of Dy and Tb: 0.01 to 10%, and B: 3 to 20%, with the balance comprising Fe and inevitable impurities; and an average particle diameter of 10 to 1,000 ?m, wherein 70% or more of the entire surface of the rare earth magnet powder is covered with a layer being rich in the content of one or two of Dy and Tb and having a thickness of 0.05 to 50 ?m.

Abstract: A rare earth magnet includes rare earth magnet particles; and amorphous and/or crystalline terbium oxide present at the boundary of the rare earth magnet particles and represented by the formula: TbOn, wherein 1.5<n?2. The rare earth magnet prevents decrease eddy current effectively.

Abstract: A Nd—Fe—B type anisotropic exchange spring magnet is produced by a method of obtaining powder of a Nd—Fe—B type rare earth magnet alloy which comprises hard magnetic phases and soft magnetic phases wherein a minimum width of the soft magnetic phases is smaller than or equal to 1 ?m and a minimum distance between the soft magnetic phases is greater than or equal to 0.1 ?m, obtaining a compressed powder body by compressing the powder, and obtaining the Nd—Fe—B type anisotropic exchange spring magnet by sintering the compressed powder body using a discharge plasma sintering unit.

Abstract: The present invention provides a rare earth magnet superior in magnetic properties and thermal stability. In an aspect of the present invention, a production method of an alloy thin ribbon for a rare earth magnet includes a step to obtain a quenched thin ribbon by feeding a molten alloy containing praseodymium (Pr), iron (Fe), cobalt (Co), titanium (Ti), boron (B), and silicon (Si) on a rotating roll and a step to apply heat treatment to the quenched thin ribbon at a heating rate within a range of 100° to 150° C./min to crystallize the quenched thin ribbon.

Abstract: A rare earth magnet to be used in a motor. The rare earth magnet comprises rare earth magnet particles. Additionally, a rare earth oxide is present among the rare earth magnet particles, the rare earth oxide being represented by the following general formula (I): R2xR?2(1?x)O3??(I) where each of R and R? is one element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu), and 0<x<1.