Domain wall pinning in the hard permanent magnet Sm2Co10Cu1.48Fe3.16Zr0.194

We have considered the ferromagnetic domain wall pinning caused by a planar type defect characterized by a change in the magnitude of the exchange constant and the uniaxial magnetic anisotropy and in the angular deviation of the magnetic anisotropy axis. Our model is appropriate for bulk material when the magnitude of the radius of curvature of the defect is not large compared to the width of the domain wall. Expressions are obtained and graphed for the coercive force due to such pinning. It is shown that the angular mismatch between the defect and the host material breaks the degeneracy between clockwise and counterclockwise rotating Bloch walls. Further, the results are applied to the Japanese commercial TDK material, Sm2Co10Cu1.48Fe3.16Zr0.194, which shows a fine cellular structure of approximately 500 A scale.