Experiments on interlayer exchange coupling

Since the discovery of antiferromagnetic (AF) interlayer coupling in 1986, numerous systems have been investigated. Generally, it is found that the coupling of ferromagnetic (F) films separated by an interlayer oscillates as a function of the interlayer thickness between F and AF type and the transition zones are characterized by 90°-type coupling. The oscillation periods are in agreement with a theory that attributes the microscopic origin of the coupling to an indirect exchange of the F layers via the electrons of the interlayer. For the 90°-type coupling, various mechanisms have been proposed, but the situation is still unclear. We present here a condensed overview of the field and communicate some of our recent results.