Pinning of domain walls in Sm(Co,Fe,Cu,Zr)(z) at finite temperatures

We discuss simulation results of models for the pinning of the domain walls in the 2:17 permanent magnet as a function of temperature. The models cons ist of three-dimensional Heisenberg spins with changed interaction constant s at a periodic array of pinning boundaries. In the presence of an external field, at moderate temperatures (T/T-c approximate to 1/3), the domain wal l can change its shape dramatically and breaks the symmetry of the pinning potential, probably due to a reduction of the exchange interaction at the p inning boundary. The high-temperature depinning field is reduced when the a nisotropy constant of the pinning boundary is reduced; even though the low- temperature depinning held is not changed by as much. This reduction of the anisotropy constant can be achieved by increasing the copper content of th e magnet. The effect of the size and the wall thickness of the pinning boun dary is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.