Giant magnetostrictive multilayers for thin film actuators

Magnetostrictive multilayers which combine giant magnetostrictive layers (amorphous Tb/sub 0.4/Fe/sub 0.6/) and layers with large magnetic polarizations (Fe or Fe/sub 0.5/Co/sub 0.5/) were prepared by magnetron sputtering. Giant magnetoelastic coupling coefficients (28 MPa at 20 mT in the case of TbFe/FeCo) are achieved at low fields, due to the magnetic polarization enhancement in such multilayers. The high magnetostriction at low-fields and the possibility to engineer the material's properties by layer thickness variation are considered to be important features for using these films as thin film actuators, e.g. in micropumps or micromotors.