Magnetic anisotropy in nano-crystalline BaFe12O19 thin films deposited under various applied magnetic fields

Abstract

BaFe12O19 thin films have been deposited on p-type Si (1 0 0) substrate employing pulsed laser deposition technique. The films have been deposited under the magnetic field of 0.15, 0.3, 0.45 and 0.6T applied transverse to the plume, keeping the substrate temperature constant at 300°C. The aim is to investigate the effect of external magnetic fields on the structural, magnetic, morphological and optical properties of the deposited thin films.A perpendicular uniaxial magnetic anisotropy is observed for the films deposited under B=0.15 to 0.6T. The estimated value of anisotropy field has increased with the increase in the applied field. The film deposited under 0.6T, also exhibited perpendicular anisotropy. The perpendicular loop saturation magnetization increases from 168 to 227.5×103A/m as the external field is increased from B=0.15 to 0.6T, respectively. The coercivity of in-plane measurements increases with the increase in the magnetic field. The films have grains of the order of few tens of nano meters on the surface. The thickness and band gap energy of the thin films increases monotonically as the applied field during deposition is increased. The maximum values of thickness and band gap energy achieved under 0.6T, are 128nm and 2.98eV, respectively.