Exchange interactions in Fe/Y multilayers

The magnetization of Fe/Y multilayers has been measured as a function of temperature. A bulk-like T3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5-300 K. The spin-wave constant B is found to decrease inversely with tFe. A simple theoretical model with exchange interactions only, and with non-interacting magnons, has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction Jb, surface exchange interaction Js and the interlayer exchange interaction JI for various Fe layer thicknesses have been obtained.