Exchange anisotropy in epitaxial NiO(001)-fcc Co bilayers

We have sputter deposited NiO-Co bilayers on MgO (001) substrates. NiO grow s epitaxially on MgO at 800 degrees C and subsequently room temperature dep osited Co films have a fcc crystal structure in epitaxy with the oxide unde rlayer. Bias fields higher than 700 Oe at 5 K were reported. Polar Kerr eff ect measurements evidence saturation fields for perpendicular magnetization up to 15 T at low temperature, proof for a strong NiO-Co exchange interact ion. The formation of a domain wall in the Co layer is a possible mechanism for such large saturation fields. (C) 2000 American Institute of Physics. [S0021-8979(00)36108-4].