| 摘要 |
PROBLEM TO BE SOLVED: To provide an R-T-B-based permanent magnet suitable as a variable magnetic force magnet for variable magnetic flux motor, having a high residual magnetic flux density and a low coersive force, and high controllability of magnetization by an external magnetic field.SOLUTION: The slope &Dgr;J/&Dgr;(H/HcJ) in a demagnetization curve below a value Hk is less than 400 kG, the R in its composition is preferably represented by (R1R2), where R1 is a rare earth element consisting of one kind or more of Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, R2 contains at least one kind of Y, Ce, La, 0.2≤x≤0.7, and T is Fe or one kind or more of transition metal element where Fe and Co are essential. |
