The electrochemical behavior of La3+ ion is investigated on a Pt electrode in the 2.5 x 10(-3) mol L-1 La(ClO4)3-7.5 x 10(-2) mol L-1 LiClO4-dimethylsulfoxide (DMSO) system. The experimental results indicate that the reduction of La3+ ion is irreversible. Some electrochemical parameters are measured. The pulse deposition technique is used to prepare La-Co alloy films. The surfaces of La-Co alloy films are uniform, compact and showed a metallic luster. The grain sizes of La-Co alloy observed by scanning electron microscope (SEM) are about 100 nm. La-Co alloy film is amorphous as proven by the X-ray diffraction (XRD). The magnetic properties of the amorphous La-Co alloy film are measured. (c) 2005 Elsevier B.V. All rights reserved.