Ni single-crystal films of (001) orientation are prepared on Cu(001) buffer layers hetero-epitaxially grown on MgO(001) single-crystal substrates by varying the thickness in a range between 40 and 500 nm. The influence of film thickness on the magnetostriction behavior under in-plane rotating magnetic fields is investigated. A 40-nm-thick film shows a four-fold symmetry in in-plane magnetic anisotropy. The magnetic anisotropy decreases with increasing the thickness and a 500-nm-thick film shows an almost isotropic magnetic property. A triangular output waveform of magnetostriction is observed when the 40-nm-thick film is measured under low magnetic fields. The triangular behavior is related with the motion of magnetic domain walls in the magnetically unsaturated film under rotating magnetic field. With increasing the magnetic field, the film approaches to magnetic saturation and the waveform shifts to a sinusoidal shape. On the contrary, the 500-nm-thick film shows sinusoidal waveforms under low rotating fields. The magnetostriction behavior of Ni(001) single-crystal film is delicately affected by the magnetization structure which depends on the effective in-plane magnetic anisotropy.
2013 The Magnetics Society of Japan