R-T-B-BASED THIN FILM PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide a permanent magnet having high coercive force. SOLUTION : An R-T-B-based thin film permanent magnet is provided which contains : R (R consists of R1 and R2, R1 is at least one or more kinds of rare earth elements not including Ho, Gd, R2 is at least one kind of rare earth elements of Ho or Gd : T (T is Fe, or one or more kinds of transition metal elements making Fe and Co must); and B, and in which : a ratio of R2 to the total rare earth amount of a main phase particle having R2T14B structure is 5.0 at% or more and 50.0 at% or less; an average primary particle diameter D of the main phase particle is 30nm to 600nm; an R1-R2-Fe phase (the ratio of R2 to the total rare earth amount in the R1-R2-Fe phase is 1.0 at% or more and 50.0 at% or less) is present in a grain boundary; and a cross-sectional ratio of the R1-R2-Fe phase occupying in the whole magnetic layer is 6.0% or more and 27.0% or less. SELECTED DRAWING : None COPYRIGHT : (C)2017, JPO&INPIT