Large magnetoresistance in LaFeO3-substituted SrRuO3 epitaxial thin films

Abstract

In this work, the magnetotransport properties of epitaxial Sr1-xLaxRu1-xFexO3 (x = 0.05, 0.10, 0.20, and 0.30) thin films grown by pulsed laser deposition on SrTiO3 (001) substrates were investigated. Compared to doping Fe into the Ru4+ site of SrRuO3, doping LaFeO3 into SrRuO3 resulted in an increase in the zero-field resistivity. A larger zero-field resistivity value in magnetic perovskite oxide is, in many cases, favorable for obtaining high magnetoresistance. The films (0.0 ≤ x ≤ 0.10) showed metallic behavior and ferromagnetic ordering, although the resistivity increased and the ferromagnetic transition temperature TC decreased with an increase in x. The thin film with x = 0.20 displayed a clear metal-to-insulator phase transition at low temperature and also displayed a well-defined resistivity minimum. This upturn in the resistivity curve is associated with the large electron-electron interaction present in the material. The magnetoresistance values increased as x increased, and we observed a large negative magnetoresistance (MR = −35%) for the thin film with x = 0.30. The observed high MR values are associated with spin fluctuation of the mobile electronic carriers in the material.