Investigation of the influence of Al layer and total film thicknesses on structural and related magnetic properties in sputtered Ni/Al multilayer thin films

The effects of parameters of Al layer thickness and total film thickness on the structural and related magnetic properties of Ni/Al multilayer films were investigated. The films were deposited by a dual sputtering. The Ni content decreased gradually while the Al content increased as the Al layer thickness increased. It was also observed that the total film thickness had little effect on the film content. All films have a face-centred cubic structure. And, the surface morphology of Ni/Al films is more uniform and homogeneous than the surface of Ni film. For magnetic analysis, the properties were strongly changed with the parameters. The saturation magnetisation, M-s of Ni film was obtained as 572 emu/cm(3) while the M-s of the Ni/Al films decreased from 441 to 298 emu/cm(3) with increasing Al content in the films caused by the Al layer thickness. And, the increase of total film thickness resulted in a decrease of M-s value. While the coercivity, H-c value of the Ni film was 90 Oe, H-c of Ni/Al films was decreased to similar to 39 Oe with the formation of multilayer structure. Ni/Al multilayers were obtained magnetically softer than the Ni film. The M-s and H-c values were significantly affected by the variation of the film content and crystal structure caused by the changes in deposition parameters. Therefore, this is a fundamental step for Ni/Al multilayers to improve the properties of these films for their potential applications in microelectronic devices.