CORRELATION BETWEEN STRUCTURE AND MAGNETIC ANISOTROPIES OF CO ON CU(110)

Magnetic anisotropies of molecular-beam-epitaxy-grown fee Co(110) film s on Cu(110) single-crystal substrates have been determined by using B rillouin light scattering and have been correlated with the structural properties determined by low-energy electron diffraction and scanning tunneling microscopy (STM). Three regimes of film growth and associat ed anisotropy behavior are identified: coherent growth in the Co film thickness regime of up to 13 Angstrom, in-plane anisotropic strain rel axation between 13 and about 50 Angstrom and in-plane isotropic strain relaxation above 50 Angstrom. The structural origin of the transition between anisotropic and isotropic strain relaxation was studied using STM. In the regime of anisotropic strain relaxation long Co stripes w ith a preferential [1(1) over bar0$]-orientation are observed, which i n the isotropic strain relaxation regime are interrupted in the perpen dicular in-plane direction to form isotropic islands. In the Co film t hickness: regime below 50 Angstrom an unexpected suppression of the ma gnetocrystalline anisotropy contribution is observed. Symmetry reflect ions based on a crystal-field formalism and discussed within the conte xt of band theory; which explicitly takes tetragonal misfit strains in to account, reproduce the experimentally observed anomalies despite th e fact that the thick Co films are quite rough.