Effects of B on Magnetic and Magnetostrictive Properties of Tb-Fe Thin Films

Abstract

The effects of B are investigated on magnetic and magnetostrictive properties of Tb-Fe thin films over a wide B content range up to 5.59 at. %. Intrinsic saturation properties such as saturation magnetization and magnetostriction are found to decrease with increasing B content. The B content dependence of in-plane anisotropy is rather complicated for thin films with a low Tb content where in-plane anisotropy of B-free thin films is weak; in-plane anisotropy deteriorates with a small B addition, but it is enhanced by the addition of a large amount of B. However, anisotropy is little affected by the B addition for thin films with the high Tb fractions where strong in-plane anisotropy already exists without the addition of B. Over the whole composition range examined in this work, the coercive force tends to decrease with increasing B content. A very large magnetostriction of 144 ppm at a magnetic field of 30 Oe, which is largest reported so far in Tb-Fe based thin films, is achieved in a (Tb_0.46Fe_0.54)_94.41B_5.59 thin film.