Structural and magnetic properties of CoTi thin films deposited by magnetron sputtering method

Abstract

Co1–xTix (x = 0.3, 0.5 and 0.7) thin films were prepared on Si (100) substrate using DC-magnetron sputtering deposition technique. A structural phase transition occurs from hexagonal to cubic crystal structure when the Ti composition is above 30 percentage. The thickness of the films obtained from X-ray Reflectivity data is about 30 nm. The average particle size of the CoTi thin films was calculated using the Atomic Force Microscopy image. The Magneto-Optic Kerr Effect measurements suggest that only Co0.7Ti0.3 thin film exhibits soft magnetic behaviour whereas the other thin films have no magnetic properties because of small grain size and reduction of inter-grain exchange interaction. Co0.7Ti0.3 thin film has twofold magnetic anisotropy. The angle-dependent coercivity (Hc) is numerically fitted with a two-phase model of magnetization reversal, which confirms the presence of magnetic anisotropy. The magnetization reversal occurs via coherent rotation of spins along the hard axis.