Stress controlled magnetomechanical instability in terfenol-D thin films

摘要

The magneto-mechanical properties of Terfenol-D thin films deposited on Si substrates were studied by magnetic and mechanical measurements of film/substrate composite cantilevers. The DELTA E effect and mechanical damping of the film were measured simultaneously. The stress in the film was controlled by annealing and deposition at different temperatures as well by the selection of the substrate material below the recrystallization temperature and determined to vary from - 500 MPa, compression, in as deposited films to +480 MPa, tension, in annealed films. This paper highlights the magneto-mechnaical response of tensioned 1 mu m nanocrystalline Terfenol-D films on 50 mu m Si substrates display a pronounced damping maximum at a magnetic field of about 1.5kOe oriented perpendicular to the plane of the film. The phenomenon is critically dependent on the orientation of the magnetic field and is the result of a magneto-mechanical instability in the Terfenol film.