Total film thickness controlled structural and related magnetic properties of sputtered Ni/Cu multilayer thin films

Abstract

In this study, the impact of total film thicknesses on the structural and magnetic properties of multilayers was investigated. The multilayer films were produced by a DC magnetron sputtering system by considering different total thickness values as x[Ni(10 nm)/Cu(30 nm)] (x = 3, 6, 7). A face centered cubic crystalline structure with (111) preferential orientation was formed for all Ni/Cu multilayers investigated. The number of grains on surface immensely increased and their size significantly decreased as the total film thickness was systematically increased. And also, the arithmetic mean roughness deviation (Ra) and root mean square (Rq) values increased with the increase of total thickness of Ni/Cu films. From scanning electron microscope and atomic force microscope results, the surface roughness increased with increasing the total thickness. The saturation magnetization (M-s), remanent magnetization (M-r) and coercivity (H-c) values were also measured. The M-s values increased from 590 emu/cm(3) to 615 emu/cm(3), M-r values decreased from 396 emu/cm(3) to 204 emu/cm(3) and H-c values gradually decreased from 116 Oe to 89 Oe as the total film thickness increased from 120 nm to 280 nm. It was found that total thickness of Ni/Cu multilayers is an effective parameter and has a considerable role to adjust the magnetic properties for the intended purposes.