1999 年 23 巻 1_2 号 p. 156-160
Fe/Tb multilayer films show a ferrimagnetic behaviour. The magnetic properties belonging to these systems, like the magnetic anisotropy or the saturation magnetization, can be varied by an thickness modulation of the single layers. The ferrimagnetism has the origin in the antiparallel coupling of two magnetic sublattices. The first sublattice is generated by the ferromagnetic Fe-layer and the second one originates from polarized paramagnetic Tb-layers. This ferromagnetic polarization of the Tb-layer is caused by an indirect long range exchange coupling between the Fe- and Tb-layers. For a detailed study of the named interaction the Fe- and the Tb layers were separated by a non magnetic metal interlayer (like Pt, Au, Cu or Ta) was observed. The sign of the coupling depends on the interlayer metal. In the case of Pt, Ta and Cu interlayers an antiparallel coupling of the magnetic moments of the Fe and Tb layers was observed. In the case of Au interlayers the coupling provides parallel orientation of the magnetic moments of the Fe layers and the induced moment of the Tb layers. In both cases of coupling the net magnetic moment of the multilayer system oscillates with increasing thickness of the non magnetic interlayer. The length of the oscillation period depends on the material of thenon magnetic metal interlayers.
