Magnetic viscosity and coercivity analysis in nanocrystalline Sm 2 Fe 15 Si 2 C ribbons

The magnetic viscosity coefficient S, susceptibility and recoil curves were measured by SQUID For nanocrystalline Sm2Fe15Si2C ribbons at temperatures ranging from 50 K to room temperature. It was found that the effect of strong intergrain exchange coupling on S and thermal activation volume in nanocrystalline Sm2Fe15Si2C can no longer be neglected, especially at high temperature. The relation between thermal fluctuation field H-f and coercivity was analyzed according to two phenomenological models. The mechanism of coercivity was mainly controlled by inhomogeneous pinning rather than a pure nucleation of reverse domain.