Oxygen vacancies effects on phase diagram of epitaxial La 1– x Sr x MnO 3 thin films

We investigated the effects of oxygen vacancies on the structural, magnetic, and transport properties of La 1– x Sr x MnO 3 ( x =0.1, 0.2, 0.33, 0.4, and 0.5) grown around a critical point (without/with oxygen vacancies) under low oxygen pressure (10 Pa) and high oxygen pressure (40 Pa). We found that all films exhibit ferromagnetic behavior below the magnetic critical temperature, and that the films grown under low oxygen pressures have degraded magnetic properties with lower Curie temperatures and smaller magnetic moments. These results show that in epitaxial La 1– x Sr x MnO 3 thin films, the magnetic and transport properties are very sensitive to doping concentration and oxygen vacancies. Phase diagrams of the films based on the doping concentration and oxygen vacancies were plotted and discussed.