Characterisations of CoFeCu films: Influence of Fe concentration

Abstract

The properties of electrodeposited CoFeCu films were studied with respect to Fe ion concentration in the electrolyte due to their interesting magnetic properties like high saturation magnetisation and low coercivity. The films were characterised in terms of microstructural and magnetic properties. From the compositional analysis, the Fe contents in the films are found to be consistent with the Fe ion concentrations in the electrolytes. With the surface morphology analysis of the films, the number of the roundish shape structures on the surface increased with increasing Fe ion concentration (>= 0.01 M Fe) whereas the CoCu films (0 M Fe) had ridged grains. The crystal structure of the films, examined by X-ray diffraction, changed from the mixed phase of the hexagonal close packed and face centered cubic (fcc) to the fcc and finally body centered cubic structure as the Fe ion concentration in the electrolyte increased from 0 to 0.04 M. And, the average grain size decreased with increasing Fe ion concentration. Magnetisation measurements by vibrating sample magnetometer displayed that the saturation magnetisation increased and the coercivity decreased as the Fe ion concentration increased. Also, it was found that the easy-axis of the magnetisation of films is parallel to the film plane. All films showed anisotropic magnetoresistance. The longitudinal and transverse magnetoresistance magnitudes of the films changed between 3.2-4.0 and 3.0-3.8, respectively. In the study, considerable differences in the microstructural and magnetic properties were observed and might be ascribed to the change of film content caused by the Fe ion concentration in the electrolyte. A high value of saturation magnetisation, M-s (1797 emu/cm(3)) is achieved under study.