HYSTERETIC MODEL FOR BARKHAUSEN NOISE AND THE MAGNETICALLY INDUCED VELOCITY CHANGE OF ULTRASONIC-WAVES IN FERROMAGNETS UNDER STRESS

The magnetomechanical hysteresis model of Sablik and Jiles is applied to Barkhausen noise and the magnetically induced velocity change (MIVC) of ultrasonic waves in stressed ferromagnets. Barkhausen noise is modeled as being proportional to the irreversible differential susceptibility (dM(irr)/dH), i.e., the rate of change of irreversible magnetization. The predicted dM(irr)/dH signal is shown to qualitatively agree with that of the experimental Barkhausen signal. The MIVC effect is modeled by adapting the single domain model of Kwun to a multidomain model. Qualitative agreement is seen with experimental behavior under both tension and compression. In formulating, the approach used by Sablik, Jiles, and Barghout to compute the magnetostriction is utilized.