Eleventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. IV France 06 (1996) C8-523-C8-526
Magnetomechanical Damping at Low TemperaturesD.N. Beshers
Henry Krumb School of Mines, Columbia University New York, NY 10027, U.S.A.
Magnetomechanical damping (MMD) at low temperatures shows marked departures from the well-established phenomenological description of MMD at room temperature. There is enhanced damping (the Bruner-Heller rise) at low amplitudes generally said to have a magnetic origin, be hysteretic, and sometimes amplitude-dependent, but the falloff in the transition to higher temperatures is frequency-dependent. A recent mode1 considers that the Rayleigh MMD at room temperature arises from successive cooperative shifts (self-similar transformations) of the whole domain structure at once. It appears that the Bruner-Heller rise in pure iron may well be a manifestation of the localized hysteretic bowing motion of domain walls, the equivalent of the Granato-Lücke damping for dislocations. For alloys, the data are supportive but incomplete.
© EDP Sciences 1996