Thermal domain drag effect in amorphous ferromagnetic materials. I. Theory

Abstract

A steady, collective translation of domain walls has been detected through direct wall observations in metallic ferromagnets subjected to a constant temperature gradient. A 60-Hz ac external field HE is used to reduce the effect of pinning forces on the walls. Three driving mechanisms, Nernst–Ettinghausen mechanism, end-drive mechanism, and isothermal end-drive mechanism, are proposed. Three pinning mechanisms, bulk pinning, surface pinning, and end pinning are believed to be effective in these materials. The region in the (dT/dx,H0E) plane corresponding to static walls has a triangular shape. We have generalized the theory to include the three pinning wells, and the corresponding theoretical phase diagrams are shown. The saturation of phase boundary is also discussed.