Gadolinium toluenesulfonate that is highly soluble in organic solvents was prepared for the first time and used as a solute in DMF for the electrodeposition of Gd-Co film. Cyclic voltammetry and chronopotentiometry were used to study the electroreduction of Gd(III) in (p-CH3C6H4SO3)(3)Gd + DMF. Experimental results indicate that the reaction of Gd(III)+3e = Gd is irreversible, the transfer coefficient a was calculated as 0.4 and the diffusion coefficient of Gd(III) to be 1.8 x 10(-7)cm(2) s(-1) at 25 degrees C. The amorphous film of Cd-Co was obtained by potentiostatic electrolysis in (p-CH3C6H4SO3)(3)Gd + CoCl2 + DMF. It is homogeneous, dense and adheres firmly to the copper substrate analyzed by SEM, EDAX and XRD. TG and DSC experiments show that the alloying temperature of the Gd-Co film is from 436.7 to 493.7 degrees C. After heat treatment of crystallization at 500 degrees C for 1 h, the alloy phase of Co,Gd can be found in XRD patterns. (C) 2000 Elsevier Science Ltd. All rights reserved.