Effect of swift heavy ion irradiation on structural and magnetic properties of GdFe1−xNixO3 (x≤0.2) thin films

The present work reports the effect of Ni doping and 200 MeV Ag15+ ion irradiation on the structural and magnetic properties of GdFe1−xNixO3 (x≤0.2) thin films grown on SrTiO3 (001) substrate by pulse laser deposition (PLD). From the XRD patterns 'c-axis' oriented growth in the pristine films is noticed, whereas after irradiation amorphization in the films is noticed. The atomic force microscopic (AFM) images reveal the increase in surface roughness with doping and irradiation as well. The irreversibility in the zero field cooled and field cooled magnetic curves indicates to the possibility of magnetic disorder in all the pristine as well as irradiated samples. Magnetization has been found to decrease with increasing Ni3+ ion substitution at room temperature whereas an enhancement in magnetization is noticed after ion irradiation for all the films. The disparity in the magnetic properties of pristine GdFe1−xNixO3 (0.0≤x≤0.2) orthoferrites thin films can be correlated to the difference in hybridization in transition metal ion and O2− ion orbitals. However, presence of strains caused by the columnar defects is responsible for the change in structural, morphological and magnetic properties in the irradiated samples.