Defects induced huge magnetoresistance in epitaxial La1–xSrxMnO3 thin films deposited by magnetic sputtering

In this work, epitaxial La1–xSrxMnO3 (LSMO) films were fabricated on SrTiO3 substrates at temperatures (Ts) ranging from 550 to 750 °C by RF magnetron sputtering. Significant Ts-dependent structural, magnetic, and magnetotransport properties were observed. The LSMO (Ts = 750 °C) film exhibits the colossal magnetoresistance (CMR) of −47% under the magnetic field (H) of 5 T. In contrast, the LSMO (Ts = 650 °C) film demonstrates a huge magnetoresistance (MR) of −98% (H = 5 T) around the metal-insulator transition temperature and –59% at 5 K. The spin-glass-like behaviors indicate that the defects, particularly the oxygen vacancies, in the epitaxial LSMO (Ts = 650 °C) films destroy the double exchange. The huge MR is related to the defect modulated magnetic structures and spin-dependent magnetotransport properties. Our work helps to understand the physical mechanism of the CMR and provides a way for tuning the magnetotransport properties of the perovskite films.In this work, epitaxial La1–xSrxMnO3 (LSMO) films were fabricated on SrTiO3 substrates at temperatures (Ts) ranging from 550 to 750 °C by RF magnetron sputtering. Significant Ts-dependent structural, magnetic, and magnetotransport properties were observed. The LSMO (Ts = 750 °C) film exhibits the colossal magnetoresistance (CMR) of −47% under the magnetic field (H) of 5 T. In contrast, the LSMO (Ts = 650 °C) film demonstrates a huge magnetoresistance (MR) of −98% (H = 5 T) around the metal-insulator transition temperature and –59% at 5 K. The spin-glass-like behaviors indicate that the defects, particularly the oxygen vacancies, in the epitaxial LSMO (Ts = 650 °C) films destroy the double exchange. The huge MR is related to the defect modulated magnetic structures and spin-dependent magnetotransport properties. Our work helps to understand the physical mechanism of the CMR and provides a way for tuning the magnetotransport properties of the perovskite films.