GIANT MAGNETOSTRICTION OF AMORPHOUS TBXFE1-X(0.10-LESS-THAN-X-LESS-THAN-0.45) THIN-FILMS AND ITS CORRELATION WITH PERPENDICULAR ANISOTROPY

The magnetostrictive behavior of amorphous TbxFe1-x (0.10<x<0.45) thin films was studied by measuring the stress derivative of the perpendicular anisotropy. Large values of the magnetostriction were found, of order 10-3, about the same as the value observed in their polycrystalline counterparts. Within this composition range, Tb45Fe55 shows a large magnetostriction with a relatively low anisotropy which makes it a good candidate for application as a magnetoelastic element. After annealing at low temperature (175°C), relaxation of both perpendicular anisotropy and magnetostriction was observed. However, the relaxation strength was particularly remarkable in the range of low Tb content (x<0.30). The relaxation behavior seems to indicate that local anelastic strain may be the origin of this bond anisotropy for low Tb content while additional structural anisotropy is likely to be responsible for the anisotropy in higher Tb content films. © 1995 The American Physical Society.