Orientational Dependence Of Oscillatory Exchange Coupling
The role of the interlayer Fermi surface in driving oscillatory exchange coupling of ferromagnetic layers has been critically tested in a series of MBE-grown coherent epitaxial sandwiches prepared on single-crystal substrates. The wedge-shaped Cu (or Cu-based) interlayers have been modified in a number of different ways, achieving orientational, compositional and structural alteration of the Cu Fermi surface. Observed phenomena include multiperiodic coupling oscillations in both the ferromagnetically and antiferromagnetically coupled regions of (lOO) -oriented Co/Cu/Co samples, extended oscillatory periods across CuNi alloy interlayers, and extremely short-period oscillations in a bcc (100) Fe/Cu/Fe system. These phenomena are straightforwardly explained in terms of calculated Fermi surface variations.