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 Co_0.7Ti_0.3 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. Co_0.7Ti_0.3 thin film has twofold magnetic anisotropy. The angle-dependent coercivity (H_c) 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.

KEYWORDS:

• DC-magnetron sputtering
• phase transition
• hexagonal
• magnetic anisotropy
• magnetization reversal
• coherent rotation

Acknowledgments

MM acknowledges Mr. Layanta Behera, Mr. Anil Gome, Ms. Zaineb Hussain, Mr. Vinay K. Ahire of UGC-DAE CSR, Indore, for preparation and characterization of alloy thin films. Authors acknowledge Dr. V. R. Reddy of UGC-DAE CSR, Indore, for his help in MOKE data analysis and interpretation and Prof. S. Varma & Mr. Ashish Manna of IOP, Bhubaneswar, for AFM data.

Disclosure statement

No potential conflict of interest was reported by the author(s).