Switching of the exchange bias in Fe/Cr(211) double-superlattice structures

The reversal of the direction of the exchange bias in a "double-superlattic e" system which consists of an Fe/Cr antiferromagnetic (AF) superlattice wh ich is ferromagnetically coupled with an Fe/Cr ferromagnetic (F) superlatti ce through a Cr spacer layer, is observed. Magnetometry and polarized neutr on reflectometry show that a switch in the bias direction occurs at a field (similar to 447 Oe) well below the field (14 kOe) necessary to saturate th e AF superlattice and well below the field (2 kOe) where the AF superlattic e initiates a spin-flop transition. The switching of the exchange bias cann ot be explained in terms of a model of uniform rotation, but rather by brea kdown into domains and reversal of the AF layers. The transparency of magne tic behavior of the double superlattice may be useful in understanding the behavior of traditional exchange bias systems. (C) 2000 American Institute of Physics. [S0003- 6951(00)00240-0].