Low field anisotropic magnetostriction of single domain exchange-coupled (TbFe/Fe) multilayers

Giant magnetostriction (GMS) reported until now in exchange-coupled multila yers (ECML) present quasi-isotropic magnetostrictive behavior. In the prese nt work it is shown the possibility to induce highly anisotropic GMS at low field with the single domain state in (TbFe/Fe)(n) multilayers when deposi ted by ion sputtering under a magnetic polarization field H-d. ECML grown u nder bias field H-d, applied along the large size of rectangular glass subs trates present original magnetic and magnetoelastic (ME) properties associa ted with strong uniaxial behavior. After saturation by an external field H- parallel to applied parallel to the easy axis induced by H-d, a single doma in state is kept by decreasing H-parallel to down to zero (Mr/Ms = 1) which explains why there is no change of the magnetoelastic coefficient b(gamma, 2) by increasing or decreasing H-parallel to. A different behavior arises a long the hard magnetization axis with a strong change of b(gamma,2) by incr easing H-parallel to up to the saturation. ME anisotropy is the origin of h igh amplitude flexural and torsional oscillation modes as observed in our E CML. (C) 2000 American Institute of Physics. [S0021-8979(00)81908-8].