Dependence of Hysteresis Loops on Thickness of Thin Nickel Films Prepared by RF Sputtering

Abstract

Nickel films of varying thicknesses between 70 and 300 nm were deposited on glass substrates by RF sputtering and their broad (111) FCC peaks were identified by X-ray diffraction. The surface roughness and sub-micron grains were revealed by scanning electron microscopy. According to vibrating sample magnetometry, the films showed hysteresis loops with comparable coercive field and saturation field for the in-plane and perpendicular magnetizations. The increase in thickness substantially increased the magnetization and the squareness of the Ni films. The thickness can be classified into 2 regimes by the variation of squareness. The films are thinner than 200 nm showed the in-plane anisotropy whereas the perpendicular anisotropy was developed in the case of the thickness above 200 nm.