EXCHANGE COUPLING IN RARE-EARTH TRANSITION-METAL MULTILAYERS FOR MAGNETIC SUPERRESOLUTION/

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 properti es of this intermediate layer from room temperature through the compen sation and Curie temperatures of the layers. The structures of interes t consist of a 400 Angstrom TbFeCo layer with perpendicular magnetizat ion, a 400 Angstrom GdFeCo layer with in-plane magnetization, and a Gd Fe intermediate layer of variable composition and thickness, The resul ts indicate that the structures are well-described by either a two-lay er 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 o f its dominant atomic moment. (C) 1996 American Institute of Physics.