Abstract: An R—Fe—B based anisotropic sintered magnet according to the present invention has, as a main phase, an R2Fe14B type compound that includes a light rare-earth element RL (which is at least one of Nd and Pr) as a major rare-earth element R, and also has a heavy rare-earth element RH (which is at least one element selected from the group consisting of Dy and Tb). In the crystal lattice of the main phase, the c-axis is oriented in a predetermined direction. The magnet includes a portion in which at least two peaks of diffraction are observed within a 2? range of 60.5 degrees to 61.5 degrees when an X-ray diffraction measurement is carried out using a CuK ? ray on a plane that is located at a depth of 500 ?m or less under a pole face of the magnet and that is parallel to the pole face.

Abstract: An R—Fe—B based rare-earth sintered magnet according to the present invention includes, as a main phase, crystal grains of an R2Fe14B type compound that includes Nd, which is a light rare-earth element, as a major rare-earth element R. The magnet includes a heavy rare-earth element RH (which is at least one of Dy and Tb) that has been introduced through the surface of the sintered magnet by diffusion. The magnet has a region in which the concentration of the heavy rare-earth element RH in a grain boundary R-rich phase is lower than at the surface of the crystal grains of the R2Fe14B type compound but higher than at the core of the crystal grains of the R2Fe14B type compound.

Abstract: An R—Fe—B based anisotropic sintered magnet according to the present invention has, as a main phase, an R2Fe14B type compound that includes a light rare-earth element RL (which is at least one of Nd and Pr) as a major rare-earth element R, and also has a heavy rare-earth element RH (which is at least one element selected from the group consisting of Dy and Tb). In the crystal lattice of the main phase, the c-axis is oriented in a predetermined direction. The magnet includes a portion in which at least two peaks of diffraction are observed within a 2? range of 60.5 degrees to 61.5 degrees when an X-ray diffraction measurement is carried out using a CuK ? ray on a plane that is located at a depth of 500 ?m or less under a pole face of the magnet and that is parallel to the pole face.

Abstract: An R—Fe—B based rare-earth sintered magnet according to the present invention includes, as a main phase, crystal grains of an R2Fe14B type compound that includes Nd, which is a light rare-earth element, as a major rare-earth element R. The magnet includes a heavy rare-earth element RH (which is at least one of Dy and Tb) that has been introduced through the surface of the sintered magnet by diffusion. The magnet has a region in which the concentration of the heavy rare-earth element RH in a grain boundary R-rich phase is lower than at the surface of the crystal grains of the R2Fe14B type compound but higher than at the core of the crystal grains of the R2Fe14B type compound.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.