Origin of the temperature dependence of interlayer exchange coupling in metallic trilayers

We study the influence of collective magnetic excitations on the interlayer exchange coupling (IEC) in metallic multilayers. The results are compared to other models that explain the temperature dependence of the IEC by mechanisms within the spacer or at the interfaces of the multilayers. As a main result we find that the reduction of the IEC with temperature shows practically the same functional dependence in all models. On the other hand, the influence of the spacer thickness, the magnetic material, and an external field are quite different. Based on these considerations we propose experiments that are able to determine the dominating mechanism that reduces the IEC at finite temperatures.