Magnetic properties of GdFe/Fe multilayered films

Spin-flopping phenomena in multilayer films consisting of two magnetic materials were investigated. In contrast to ordinary ferrimagnets, in which spin flopping occurs under very strong fields, multilayer films can be designed to exhibit spin flopping under rather weak fields. Samples were prepared by alternate deposition of Gd-rich amorphous GdFe alloy and pure Fe, and spin-flopping processes were studied at room temperature. Since the magnetization of a pure Fe layer is larger than that of a GdFe layer, under weak magnetic fields the Fe layer magnetization of a pure Fe layer is larger than that of a GdFe layer. Under weak magnetic fields the Fe layer magnetization is aligned in the direction of the external field, whereas that of the GdFe layer is antiparallel. At a certain critical field, the magnetization of the GdFe layer begins to turn in the direction of the external field. The field dependence of the magnetization is accounted for by assuming a twisted spin structure in the GdFe layer.