ON THE COUPLING BETWEEN THE DOMAIN-WALL COERCIVITY AND SUSCEPTIBILITY

The experimental value of the domain wall coercive field does not depend on magnetic parameters and material defects only, but it is also strongly influenced by the current domain configuration in the sample. The investigation of the global conditions of the domain walls (the wall position restoring forces expressed through the effective field gradients and/or the domain structure differential susceptibility) is the proper key to the description of this influence. As far as it is possible to introduce domain structures with different values of susceptibility into the same sample (e.g. by conditioning the sample history or by currently applied fields), that far the actual domain wall coercive field value can be modified. Based on a previously published theory and in agreement with the presented experiments in epitaxial magnetic garnet films, a roughly linear proportionality is exhibited between the domain wall coercive field and the reciprocal value of the sample domain structure susceptibility. The way of a magnetostatic control of the domain wall coercive field and hysteresis losses in soft magnetic materials is suggested and tested