MAGNETOMECHANICAL DAMPING AT LOW-TEMPERATURES

Magnetomechanical damping (MMD) at low temperatures shows marked depar tures front die well-established phenomenological description of MMD a t room temperature. There is enhanced damping (tile Bruner-Heller rise ) at low amplitudes generally said to have a magnetic origin, bt:hyste retic, and sometimes amplitude-dependent, but the falloff in the trans ition to higher temperatures is frequency-dependent. A recent model co nsiders that the Rayleigh MMD at room temperature arises from successi ve cooperative shifts (self-similar transformations) of die whole doma in structure at once. It appears that die Bruner-Heller rise in pure i ron may well he a manifestation of tile localized hysteretic bowing mo tion of domain walls, tile equivalent of the Granato-Lucke damping for dislocations. For alloys, tilt: data are supportive but incomplete.