Temperature dependence of interlayer coupling in Fe/Si superlattices

We have explored the temperature dependence of the interlayer coupling in Fe/Fe1-xSix superlattices (0.5 less than or equal to x less than or equal to 1). It is found that the Si content of the Fe1-xSix, spacer greatly affects the temperature dependence of the bilinear and biquadratic coupling constants. Neither the "thickness fluctuation" model nor the "loose" spin model proposed by Slonczewski give satisfactory explanations to the temperature-dependent interlayer coupling. Instead, the present experimental results for all spacer compositions can be reproduced very well by the quantum interference model. We discuss the experimental results based on the above interlayer coupling models.