Magnetic viscosity of nanocomposite Sm-Fe-Cu-Zr-Ga-C ribbons

The magnetic viscosity was investigated at temperatures between 100 and 293 K for the nanocomposite Sm2Fe18.25Zr0.25Cu0.5Ga2C2 ribbons prepared by melt -spinning and subsequent annealing. It was found that the maximum S and chi (irr), located near coercivity, increase with increasing temperature. The v iscosity parameter S-v was found to be strongly dependent on the applied fi elds at lower fields than the coercivities. The relation between S-v and co ercivity was analyzed. The coercivity mechanism is mainly controlled by dom ain-waIlpinning. The activation volume associated with mngnetiaation revers al, which can be calculated from S-v, is much smaller than the grain volume .