In the asymptotic limit, the interlayer exchange coupling decays as D <Superscript>−2</Superscript>, where D is the spacer thickness. A systematic procedure for calculating the preasymptotic corrections, i.e., the terms of order D <Superscript>−n </Superscript> with n ≥ 3, is presented. The temperature dependence of the preasymptotic...</superscript></superscript>