Stress-induced magnetic anisotropy in Xe-ion-irradiated Ni thin films

Samples consisting of 75 nm Ni films deposited on Si substrates were bent mechanically and irradiated with 200 keV Xe-ions at a dose of 4 × 1014 ions/cm2. Magneto-optical Kerr effect, Rutherford backscattering spectrometry and X-ray diffraction were used to investigate the changes in the magnetic and microstructural properties. Perfect uniaxial magnetic anisotropy was found in the Ni films after irradiation and removal of the samples from the target holder. The magnetic behavior is shown to be very sensitive to the external stress produced in the films. With increasing curvature of the bent samples (≈2 m−1), the easy axis of the magnetic anisotropy rotated in the direction perpendicular to the bending axis, indicating a compressive stress in the films after irradiation and relaxation.