Temperature dependence of domain-wall bias and coercivity

Some models for exchange bias at the interface of a ferromagnet and antifer romagnet involve the formation of partial domain walls in the antiferromagn et layer. Numerical calculations of mean-field temperature dependence are u sed to examine thermally induced instabilities in the partial domain wall a t ideal compensated and uncompensated antiferromagnet interfaces. At compen sated interfaces, depinning of the partial wall results in a total loss of bias. At uncompensated interfaces, thermal effects at the interface cause t he wall to move into the antiferromagnet. The critical fields for this part ial depinning are different for the forward and reverse magnetization direc tions. This mechanism on uncompensated interfaces allows for simultaneous l oop shift and coercivity, which is not found in the compensated case. (C) 2 001 American Institute of Physics.