Bandgap tuning, high electrical conductivity, and room-temperature ferromagnetism in La- and V-doped SrSnO3 epitaxial films

In this study, La- and V-doped SrSnO3 epitaxial films were fabricated via pulsed laser deposition, and the effects of doping on the structure and physical properties of films were systematically investigated. Detailed x-ray diffraction characterization demonstrates that the lattice parameters of V-doped SrSnO3 (SrSn1-xVxO3, x = 0-1, SSVO) films decrease gradually as the V content increases. The optical bandgap first increases from 4.43 to 4.56 eV and then decreases to 3.31 eV with the increasing V content. Density functional theory calculations indicate that the strong hybridization between Sn 5s and V 3d orbitals causes an initial expansion of the bandgap. Doping SSVO films with 5% La greatly improves the electrical conductivity. Hall-effect measurements show that the (La0.05Sr0.95)VO3 film has the lowest room-temperature resistivity of 0.05 m omega & nbsp;cm and correspondingly the largest carrier density of 1.79 x 10(22) cm(-3). Ferromagnetism in SrSn1-xVxO3 films is highly dependent on V concentration at room-temperature, and the origin of ferromagnetism may be explained by the bound magnetic polaron model.