Influence of surface roughness on magnetic properties of CoTbNi ternary alloy films

Abstract

Rare earth-transition metal (RE-TM) amorphous alloys films with promising tunable perpendicular magnetic anisotropy are projected to be exploited for magnetic recording media and spintronic applications. Here variation of magnetic property of thin films of Co0·63Tb0·11Ni0.26, Co0·41Tb0·14Ni0.45 and Co0·32Tb0·08Ni0.60 ternary alloy fabricated on Si-substrate using dc magnetron sputtering at room temperature were studied. The x-ray diffraction pattern data confirms the amorphous nature of these alloy films. The average surface roughness (Sa and Ra) of the films is found to vary significantly with Ni content of the films. The room temperature field dependent magnetization measurement shows the room temperature ferromagnetism. The saturation magnetization and coercivity of the M-H curves are found to vary with Ni content as well as surface roughness of the films. However, the nature of variation of saturation magnetization and coercive field is in accordance with variation of surface roughness, indicating that film surface roughness play a vital role in tuning the magnetic properties of these thin films. Such tunable magnetic properties of these amorphous films make them good candidate for magnetic storage media applications.