SPACER-LAYER-INDUCED SPIN REORIENTATION IN NI CU/NI SANDWICHES/

We report polar magneto-optical Kerr effect studies of Cu spacer layer on the perpendicular magnetic anisotropy in 70 Angstrom Ni/Cu wedged/ 70 Angstrom Ni structures. With increasing Cu thickness, the magnetic easy axis of the top Ni layer continuously changes to the direction pe rpendicular to the surface. This results from the gradual strain relax ation of the Cu spacer with increasing thickness followed by increasin g strain in the top Ni layer. A crossover from coherent to incoherent strain in Cu spacer around 18 Angstrom results in a dramatic non-monot onic dependence of magnetic anisotropy on the Cu thickness.