Properties of Co–Fe Films: Dependence of Cathode Potentials

摘要

Co–Fe films were electrodeposited on Titanium substrates at the cathode potentials changing from ${-}$ 1.8 to ${-}$ 2.7 V with respect to saturated calomel electrode (SCE). The structural analysis by X-ray diffraction revealed that all films have a mixed phase of face centered cubic and body centered cubic structure, but the phase ratios change depending on the cathode potentials. The compositional analysis, which was made using an energy dispersive X-ray spectrometry, demonstrated that the Co content of the films slightly increases as the deposition potential increases. The morphological analysis of the films grown at high deposition potential (${-}$2.7 V versus SCE), studied by scanning electron microscopy, indicate that they have larger grains. All Co–Fe films showed anisotropic magnetic resistance up to 4% and its magnitude was affected by the cathode potentials. Magnetic measurements carried out by the vibrating sample magnetometer indicated that the saturation magnetization varied and the coercivity decreased from 46.98 to 31.74 Oe as the cathode potential increased. The easy axis of magnetization was found to be in the film plane for all films. The variation in magnetoresistance and magnetic properties may be related to the structural changes in the films.