Coercive force variations in externally stressed Ni films

Kerr magneto-optical measurements have been performed on Ni films deposited on glass subjected to the influence of an external stress. It has been observed that the coercive force increases for tensile stress perpendicular to the magnetic field, and decreases, in the opposite case, at variance with respect to bulk Ni. Our data can be qualitatively understood in terms of the simple theory of Stoner and Wohlfarth (SW) which is valid for single domain magnets with uniaxial anisotropy. A computer simulation of the effect of stress based on an extension of the SW model to a multidomain system shows a good qualitative agreement with the experimental data.