Studies of dynamic magnetostriction by time-resolved scanning fiber interferometry

Measurements of the magnetostrictive response of nickel cylinders to sudden step changes in applied magnetic field are performed with a time-resolved scanning fiber interferometer. A crossover is observed, as a function of decreasing cylinder diameter, from eddy current- to longitudinal phonon-limited response times. Spatially resolved measurements reveal the nonuniform distortion of the face of the rod as the induced magnetization propagates in toward the center. The results demonstrate, here in the context of magnetics, the general promise of time-resolved scanning probe methods.