Thickness dependent magnetic properties of (111)-oriented Co 0.8 Fe 2.2 O 4 thin film grown by pulsed laser deposition

The perfect (111)-oriented Co0.8Fe2.2O4 thin films are grown on Pt(111)/Si substrate using pulsed laser deposition technique at substrate temperature of 600°C and laser pulse rate of 5 and 10Hz. The Fe K-edge X-ray absorption near edge structure analyses revealed that Fe in Co0.8Fe2.2O4 films deposited at both 5 and 10Hz exists in Fe3+ state leading to the actual composition of Co0.8Fe2.2O4+δ. In order to study the effect of film thickness on the magnetic properties, the film thickness was increased by increase in the pulse rate as well as the time of deposition during pulsed laser deposition process. It was found that by increase of the film thickness, the saturation magnetization and squareness will be generally increased. In the films with same thickness, those which deposited at higher pulse rate have a higher coercivity. In the films deposited at same pulse rate (10Hz) and different time of deposition, the saturation magnetization, coercivity, and squareness were increased by increasing the thickness, but the coercivity will be decreased with further increasing the thickness due to the relaxation of residual stresses.