Electrochemical preparation La–Co magnetic alloy films from dimethylsulfoxide

Abstract

The electrochemical behavior of La³⁺ ion is investigated on a Pt electrode in the 2.5 × 10⁻³ mol L⁻¹ La(ClO₄)₃–7.5 × 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.

Introduction

Rare earths and their alloys exhibit interesting magnetic, optical, electric, and hydrogen storage properties, that have been widely applied to the development of various functional materials [1], [2], [3]. La–Co alloys possess magnetic properties. The main interest of the study is focused on magnetic properties associated with the interfacial spin polarization induced in a 3d transition metal (TM) by a rare earth (RE) element via the 4f–3d interaction, through the 5d–3d hybridisation. The thin-film structures have been found useful in a wide range of applications in a few years. The properties of low-dimensional layered structures are quite different from those found previously in bulk materials [1]. La–Co alloy films have mainly been prepared through physical methods [4], [5]. Since rare earth elements are very active, it is very difficult to deposit them from aqueous solution using electrochemical methods. Recently, we have studied the electrodeposition of rare earths and their alloys from organic solutions at room temperature [6], [7]. In this paper, the kinetic parameters of La³⁺ ion are measured and La–Co alloy films are prepared by pulse electrodeposition in dimethylsulfoxide (DMSO).