Contrasts in the coercivities of SmCo5 and Sm2Co17-type permanent magnets

Abstract

We have extracted the intrinsic coercivity, saturation magnetization, and anisotropy field from M‐H loop measurements in the TDK Sm₂(Co, Fe, Cu, Zr)₁₇ and the Hitachi SmCo₅ permanent magnetic materials from liquid helium to room temperature. The TDK sample exhibits a coercivity in the hard direction which is larger than in the easy direction, while the reverse situation is true for the SmCo₅ sample. This behavior is linked to the difference in the mechanisms of magnetization dominating the sample, wall domain motion for the TDK sample, and domain nucleation for the SmCo₅.