COERCIVE FORCE IMPROVED PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide a permanent magnet capable of significantly improving a coercive force without depending on a heavy rare earth element such as rare Dy.SOLUTION : The permanent magnet includes, on its surface, a recess pattern formed by distributing recesses for which a maximum length ratio (d/D) that is a ratio of a maximum length (d) to a unit magnetic domain diameter (D) peculiar to the permanent magnet is equal to or less than 20 and an interval ratio (w/D) that is a ratio of a neighboring interval (w) to the unit magnetic domain diameter is equal to or less than 10. On the surface of the permanent magnet, the movement of a magnetic wall is prevented by a number of recesses which are set on the basis of the peculiar unit magnetic domain diameter in accordance with a kind (composition or the like) of the permanent magnet, and coercive force improvement is attained. In the case of a rare earth magnet formed from R2Fe14B, for example, it is preferable that the maximum length is equal to or less than 4 μm and the neighboring interval is equal to or less than 2 μm.COPYRIGHT : (C)2016, JPO&INPIT