Estimation of effective magnetic field in an iron bar by the ultrasonic resonance method

In this paper the strength of the effective field, H_eff, is estimated along a rod specimen by transmitting ultrasonic waves to the specimen. The iron bar used in the study has a size 5×5 mm² in cross section and 100 mm in length. The effective field, H_eff, is calculated from the magnetization curve and demagnetization factor of the specimen. The dependence of the electromotive force (emf) due to ultrasonic waves on H_eff at the center node of bar in the stationary state is presented. The magnetostriction measured at the center of the iron bar is also presented.