Magnetic and magnetostrictive properties of amorphous Tb(1-x)Cox thin films

Magnetostrictive thin films are currently of great interest for use as active materials in integrated microactuators. We have studied a series of Tb1-xCox amorphous thin film samples and found large magnetostriction at room temperature with ordering temperatures up to about 600 K, higher than those for amorphous Tb-Fe alloys. Here we present the magnetic and magnetostrictive investigations for Tb1-xCox in a range of 0.48 less than or equal to x less than or equal to 0.78. For the ferromagnetic samples at room temperature (x > 0.62) the intrinsic anisotropy is analysed in terms of a biaxial anisotropy model. No saturation was observed for fields up to ST, due to the sperimagnetic nature of such materials. A maximum in magnetostriction was found (x = 0.71) with values of b(gamma,2) = 24 MPa (i.e., lambda(gamma.2) = 400 x 10(-6)). (C) 1999 Published by Elsevier Science B.V. All rights reserved.