Atomistic calculation of the thickness and temperature dependence of   exchange coupling through a dilute magnetic oxide
  The exchange coupling of two magnetic layers via a diffuse oxide interlayer is studied with an atomistic spin model. We investigate the effect of magnetic concentration and oxide layer thickness on the effective exchange coupling strength and find an exponential dependence of the coupling strength on the oxide thickness without the need for magnetic pinholes. Furthermore we show that exchange coupling has a strong temperature dependence which is significant for the reversal dynamics during heat assisted magnetic recording. 
R. F. L. Evans, Q. Coopman, S. Devos, W. J. Fan, O. Hovorka and R. W.   Chantrell
cond-mat.mtrl-sci