Exchange coupling in rare-earth/transition-metal multilayers for magnetic super-resolution

Abstract

We study exchange coupling in rare-earth/transition-metal multilayers in which one layer has perpendicular magnetization and a second layer has in-plane magnetization at room temperature. The exchange coupling between these layers is mediated by a thinner intermediate layer, and we investigate the dependence of the exchange on the magnetic properties of this intermediate layer from room temperature through the compensation and Curie temperatures of the layers. The structures of interest consist of a 400 A TbFeCo layer with perpendicular magnetization, a 400 Å GdFeCo layer with in-plane magnetization, and a GdFe intermediate layer of variable composition and thickness. The results indicate that the structures are well-described by either a two-layer or a three-layer coherent rotation model (depending on intermediate-layer thickness) and that the influence of the intermediate layer is a function of its anisotropy energy, its thickness, and the identity of its dominant atomic moment. © 1996 American Institute of Physics.