FINITE-SIZE EFFECTS IN THIN GADOLINIUM FILMS

Magnetic transition studies have been made by measuring the electrical resistivity of thin Gd films as a function of temperature. The shift of the Curie temperature, T-c, with film thickness, d, can be characte rized by a critical exponent, lambda, such that [T-c(infinity) - T-c(d )]/T-c(ca) similar to b/d(lambda). The value of the shift exponent lam bda was found to be 0.91 +/- 0.02. The effect on T-c of annealing the Gd films has also been examined. The values of T-c obtained from elect rical resistivity measurements are independent of annealing temperatur es up to 573 K for 30 minutes.