Domain wall pinning in high temperature SM(Co, Fe, Cu, Zr)7-8 magnets

A finite element method was used to simulate domain wall pinning in SmCo5/Sm2Co17 based permanent magnets. The finite element model was built according to the cellular microstructure obtained from transmission electron microscopy investigations. The numerical results show a strong influence of the dimension of the cell boundary phase on the coercive field, which significantly increases with the extension of the 1:5/7-type cell boundary phase. The calculated values of the coercive field are in the range from 1000 to 2000 kA/m assuming a cell size varying from 80 to 160 nm. The difference of the magnetocrystalline anisotropy between cell boundary and cell interior phases is determined by the Cu content of the magnet.