Magnetic field effects on surface morphology and magnetic properties of Co–Ni–P films prepared by electrodeposition

Abstract

In this paper we investigated the effect of the direction of an external magnetic field, applied during electrodeposition, on the magnetic properties and morphology of Co–Ni–P layers. The films (400 nm thickness) were electroplated on Cu plane substrates using the same electrodeposition parameters (temperature, pH and current density) for all experiments, with a magnetic field of 120 kA m −1 applied so that the magnetic flux lines were horizontally parallel or perpendicular to the cathode surface. The films were compared with similar samples obtained in the absence of magnetic field. We observed that an induced anisotropy appeared in the Co–Ni–P films due to the preferential orientation of the easy axis of magnetization in the magnetic field direction. These films presented also changes of the surface topography and phase images of the surface. The magneto-induced modifications in the Co–Ni–P morphology can be explained by the specific local convection of ions at the interface cathode–electrolyte, which promotes changes both in the electrical charges of the double layer and in the thickness of the diffusion layer.