Magnetic and structural properties of ion-beam-sputtered thin films of (Co 90Cr 10) 100 − xTM x where TM denotes vanadium, niobium, molybdenum or tantalum

Abstract

With a view to possible applications as perpendicular recording media, thin films of composition (Co 90Cr 10) 100 − x TM x were made, where TM denotes vanadium, niobium, molybdenum or tantalum and x is between zero and 20 at.%. The films were prepared by ion beam sputtering from composite targets. The basic magnetic properties such as anisotropy and coercivity were determined. The magnetization was also studied as a function of temperature. A very striking result is the relatively low coercivity for TM ≡ V (about 500 Oe), which is independent of substrate temperature. X-ray diffraction revealed strong structural variations with different transition metals. With molybdenum and tantalum substitutions, films with a sharp [00.1] texture were obtained leading to perpendicular anisotropy. Transmission electron microscopy on thinner films showed the films with TM ≡ Nb, Mo and Ta to be microcrystalline or amorphous. In contrast, the (Co 90Cr 10) 100 − x V x films were coarse grained; this is possibly related to their relatively low coercivity and broad [00.1] texture.