FE CR MULTILAYERS - EFFECT OF ANNEALING ON THE SPIN STRUCTURE AND MAGNETORESISTANCE/

The spin structure of antiferromagnetic Fe/Cr multilayers has been inv estigated by polarized neutron reflectivity. Measurements were taken o n freshly sputtered films as well as films annealed at different tempe ratures. For annealing temperatures up to 350-degrees-C adjacent Fe la yers were found to remain antiferromagnetic, but the coupling strength gradually decreases. In multilayers annealed at higher temperature bo th antiferro- and ferromagnetic phases are present. In all cases the m agnetoresistance is proportional to the amount of antiferromagnetism. The presence of off-specular, diffuse scattering around the antiferrom agnetic Bragg peak indicates that the magnetic domains are laterally l imited; however, their size is not correlated directly to the magnetor esistance.