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 &mgr;m and a minimum distance between the soft magnetic phases is greater than or equal to 0.1 &mgr;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: A rare earth magnet comprises rare earth magnet particles and a rare earth oxide being present between the rare earth magnet particles.

Abstract: An electrical-steel-sheet formed body is provided with an opening portion into which a permanent magnet is inserted, and an outer-peripheral hardened portion formed on the electrical-steel-sheet formed body at an outer periphery side thereof for the opening portion and having a higher hardness than a remaining area of the electrical-steel-sheet formed body. The electrical-steel-sheet formed body can be used as the rotor of the built-in permanent magnet type rotary electric machine, and the built-in permanent magnet type rotary electric machine can be obtained.

Abstract: An exchange-spring magnet is prepared using a magnet alloy containing Ta and C in addition to Nd, Fe and B. This exchange-spring magnet uses the magnet alloy prepared by a liquid quenching method or a mechanical alloying method. Further, by subjecting the magnetic alloy having a part set in an amorphous state to heat treatment, an exchange-spring magnet exhibits good properties regarding magnetic flux density and coercive force.