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 λ 100 magnetostriction constant controls the effects on both the remanence ratio and anisotropy field. When the anisotropy is positive, the λ 111 constant is predominant. For a single-crystal specimen of Y 3 Fe 5 O 12 , quantitative agreement with the theory was obtained from measurements carried out on a hysteresigraph. Polycrystalline samples of Y 3 Fe 5 O 12 , Y 1.4 Ca 1.6 V 0.8 In 0.5 Fe 3.7 O 12 , and Y 3 Mn 0.1 - Fe 4.9 O 12 were examined in a more qualitative manner and these results were also in accord with theory.