Study of tilted orthorhombic twins and leakage current in epitaxial SmFeO3 thin films

The effect of oxygen partial pressure (OPP) during deposition on the structural and ferroelectric properties of epitaxial SmFeO3 (SFO) thin films is studied in the present report. The thin films are deposited using the pulsed laser ablation method. Two (00l) oriented substrates, viz., LaAlO3 (LAO) and niobium doped SrTiO3 (Nb:STO), are used for the deposition of films with 35 and 170 nm thicknesses at different OPP values. The prepared films are found to be of single phase and grow in the out-of-plane configuration SFO(hh0)/LAO(00l) using x-ray 2θ−ω and ϕ scans. The epitaxial relationship between the substrate and the film, domain twinning, is confirmed by reciprocal space map measurements. Films of higher thickness exhibit tilted twin structures, more prominently for the films prepared at lower OPP. A significant change in the leakage current is observed as a function of OPP, and the results are explained in terms of the microstructure of the films.