Magnetic interface walls under applied magnetic fields

Abstract

In experiments with exchange-coupled double layers (ECDL) consisting of two ferrimagnetic layers of different composition of the general system GdTb–FeCo, it is observed that the interface wall changes its position under external fields. Furthermore, it was found that the interface wall energy σw determined on the same ECDL can be markedly different, depending on which of the two layers’ reversal curves it was determined. It is hypothesized that this effect is due to the different external fields at which the experiments have been performed. In order to check this hypothesis, a series of bilayers with different thicknesses of the ‘‘soft’’ layer was prepared, so that the reversal loop from which σw is determined occurs at different fields. The theoretical dependence of the interface-wall energy on the external field as obtained from computer simulations is found to be weaker than the experimental one.