TRANSITION FROM ANTIFERROMAGNETIC COUPLING TO BIQUADRATIC COUPLING INFE FESI MULTILAYERS/

The detailed temperature dependence of interlayer exchange coupling in Fe/FeSi multilayers prepared by ion beam sputtering was investigated and compared with the data for Fe/Si multilayers. Significant differen ces between interlayer exchange coupling in Fe/FeSi and Fe/Si multilay ers were observed. The coupling between Fe layers in Fe/FeSi multilaye rs showed a transition from antiferromagnetic to 90 degrees coupling w ith decreasing temperature. This was due to the strong temperature dep endence of J(2) (biquadratic coupling), which outweighs that of J(1) ( collinear coupling) at low temperatures.