Effect of external stress on remanence ratios and anisotropy fields of magnetic materials

Changes in shape of the hysteresis loops of magnetic materials with compressive stress applied parallel to the magnetic field have been studied both theoretically and experimentally. From a model of a single independent grain, the results of theory suggest that for materials with negative anisotropy, the λ100magnetostriction constant controls the effects on both the remanence ratio and anisotropy field. When the anisotropy is positive, the λ111constant is predominant. For a single-crystal specimen of Y3Fe5O12, quantitative agreement with the theory was obtained from measurements carried out on a hysteresigraph. Polycrystalline samples of Y3Fe5O12, Y1.4Ca1.6V0.8In0.5Fe3.7O12, and Y3Mn0.1- Fe4.9O12were examined in a more qualitative manner and these results were also in accord with theory.