MAGNETIC-ANISOTROPY AND LATTICE STRAIN IN CO PT MULTILAYERS/

The correlation is reported between perpendicular anisotropy and in-pl ane lattice strain in Co/Pt multilayers. (Co(x)/Pt(y))n samples, where x, y are the thickness of the individual Co and Pt layers and n is th e number of repeats that were prepared by molecular beam epitaxy and s tudied by means of polar magneto-optic Kerr effect and transmission el ectron microscopy. Kerr rotation data and electron diffraction experim ents show that the largest perpendicular anisotropy and square hystere sis loop occur when x = 3 angstrom while the Pt layers are subjected t o about -2% in-plane strain. As Co thickness increases, Co and Pt laye rs gradually lose coherency and the magnetic anisotropy goes from perp endicular to planar. This is accompanied by a relaxation of lattice st rain in both Co and Pt layers. The close relationship between magnetic anisotropy and lattice strain can be explained as magnetoelastic anis otropy or stress anisotropy effect due to lattice mismatch between the adjacent epitaxial layers.