Proximity-induced short-range spin density wave order in Fe/Cr multilayers

To describe the magnetic phase diagram of Fe/Cr multilayers we propose an a pproach based on the Ginzburg-Landau expansion of the free energy in terms of a spin density wave ( SDW) order parameter which is determined self-cons istently. This approach shows the existence of short-range order with a cha racteristic width D close to the interfaces. Although not homogeneous this phase resembles the commensurate SDW identified in neutron experiments and determines the observed high-temperature transition temperature T-1. The de pendence of T-1 on the Cr thickness L is in agreement with the experimental behaviour and the length 2D can be identified with the critical Cr thickne ss for the existence of the incommensurate SDW.