MULTITARGET SPUTTERING OF HIGH MAGNETOSTRICTIVE TB-DY-FE FILMS

Giant magnetostrictive thin films of both the binary compound ThxFe1-x and the ternary compound (TbyDy1-y)xFe1-x have been prepared by multitarget magnetron sputtering in wide compositional ranges. In view of their potential use as actuators in microsystem technology the research was focused on low-field magnetostrictive properties in connection with low coercivity. Giant magnetostriction was found for a range of compositions with Th contents higher than those of the crystalline Tb-Fe compounds. Depending on, the composition, amorphous films with a magnetostriction as large as lambda almost-equal-to 450 X 10(-6) at an applied field of 6 kOe and a coercive field H(c) < 10 Oe could be prepared. The improvement of the low-field magnetostriction of the ternary alloy Tb-Dy-Fe in comparison to Tb-Fe was found to be less distinct than for crystalline materials, probably because all reported films showed a perpendicular easy axis. The amorphous state of the films are stable at least up to 300-degrees-C.