Probing oscillatory exchange coupling with a paramagnet

A paramagnet is used to probe directly the exchange coupling emanating from a ferromagnetic specimen across a nonmagnetic spacer material by measuring the induced magnetic moment. The model structure to observe the oscillatory exchange field consists of a Cu(100) single crystal, a Co base layer, a Cu spacer, and fcc Fe as the paramagnetic probe layer with large magnetic susceptibility. Spin-resolving techniques show that the magnetization of the paramagnet oscillates as a function of the thickness of the spacer as well as of the paramagnet. © 1995 The American Physical Society.