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

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.