Influence of nickel doping on structural, morphological and mechanical properties of BiFeO3thin films

This paper presents the effect of incorporation of Ni-substitution (0-20 at %) on structural, morphological and mechanical properties of BiFeO3 films. The films are found to be in polycrystalline perovskite phase with no additional NiO phase. The (012) and (110) x-ray diffraction peaks of the films are found to be gradually shifting towards the lower diffraction angle side due to the generation of higher biaxial strain with the increase in Ni substitution in BiFeO3 lattice. Average grain size of the films is increased from 55 nm (pristine) to 90 nm (20 at % Ni). Measuredelastic modulus (51-80 GPa) and hardness (7.5-14.5 GPa) of the BiFeO3 films are found to be increasing with the Ni incorporation. The improved mechanical properties of the films are seems to be due to the collective effects of the bi-axial tensile strain, nano-structured grains and substitution of Fe atoms with high elastic material like Ni.