Non-linear actuation of cantilevers using giant magnetostrictive thin films

In the present paper, we report the first results concerning a centimetre c antilever driven through non-linear effects in thin magnetostrictive films. Bimorph centimetre beams (24 mm x 5 mm) were designed using 160 mu m thick glass and 0.4 mu m thick multilayer TbFe/Fe films deposited via RF sputter ing, using several sputtering conditions. Dynamic magneto-elastic excitatio ns were studied experimentally on the few eigenresonance modes of the canti levers. Sub-harmonic excitation at half or one-third of the frequency of an eigenresonance mode has been achieved near the spin reorientation transiti on and the efficiency is as good as for eigenfrequency excitation. Specific magnetic properties of the samples led to a model of the thermodynamic pot entials and behaviour of the excited resonator. (C) 2000 Elsevier Science B .V. All rights reserved.