Abstract
Flexural and torsional motions have been investigated in low field anisotropic giant magnetostrictive (GMS) single domain state (SDS) exchange-coupled Tb/Fe/Fe multilayers (ECML). The magnetoelastic (ME) coefficient bγ,2 and susceptibility db/dH depend strongly on the ECML structures, compositions, sputtering deposition parameters and post-deposition heat treatments. Due to a well defined but low uniaxial anisotropy associated with the SDS induced by a bias field during the film deposition, a Spin Reorientation Transition (SRT) with quasi-static and resonant bi-stability properties is clearly achieved near the saturation field along the hard axis. Harmonic and subharmonic excitations of first and higher-orders (linear and non-linear excitations) of flexural and torsional oscillations modes with huge amplitudes have been stimulated from the SRT in agreement with our theoretical model. The corresponding very large dynamical ME susceptibility gives the possibility to control GMS micro-electromechanical systems (MEMS) with a strong reduction of the excitation field.
