Magnetic Anisotropy in Single-crystal Nickel Films

Abstract

Single-crystal thin films of nickel, in the thickness range 50-500 A have been prepared, by epitaxial growth on rock-salt, and their magnetic anisotropy measured. All films show a uniaxial anisotropy superposed on the normal cubic anisotropy. In the discontinuous films, annealing in vacuum reduces the uniaxial component whilst in continuous films annealing increases it. Films grown in a vacuum of 10-7mm are found to have few imperfections visible in the electron microscope and give more consistent results. The uniaxial component of anisotropy is shown to be a function of thickness, and is affected by the degree of vacuum achieved during deposition. It is suggested that the mechanism of directional ordering of oxygen atoms in the metal lattice, as proposed by Heidenreich, Nesbit and Burbank in 1959 would account for the results.