Application of the magnetoelectric effect to exchange bias

Owing to its magnetoelectric properties the antiferromagnetic ( AF) domain structure of Cr2O3 can be controlled when cooling through the Neel- point in simultaneously applied magnetic and electric fields. Recently we achieved complete switching of the perpendicular exchange bias field from positive to negative values and vice versa by variation of the applied electric freezing field at constant external magnetic field in the system Cr2O3/[Co/Pt](n) [ P. Borisov, et al., Phys. Rev. Lett. 94 ( 2005) 117203]. In order to image uncompensated spins at the ferromagnetic - AF interface, X- ray photoemission electron microscopy ( X- PEEM) was performed on Cr2O3 ( 1 1 1)/ Pt/ Co/ Pt heterolayers after cooling in magnetic and electric freezing fields. The orientation of the uncompensated spins and the magnetic structure at the interface measured at the Cr and the Co L-3,L-2 absorption edges are discussed. (c) 2006 Elsevier B. V. All rights reserved.