Effects of nitrogen pressure on microstructures and properties of Sr2Fe10/9Mo8/9O6 thin films

High quality double perovskite Sr2Fe10/9Mo8/9O6 thin films have been prepared on (111)-SrTiO3 substrates under different N2 partial pressures (0.1–20 Pa). The films are (111)-oriented with flat surfaces and sharp film/substrate interfaces. The epitaxy and local Fe/Mo ordering are revealed by high resolution transmission electron microscopy and selected area electron diffraction. It is established that the N2 pressure has significant effects on structures and properties: With increasing N2 pressure, the film thickness decreases and the strain increases, while the magnetization decreases monotonously. Interestingly, all the films show semiconductor-like behavior in the whole measuring temperature range but the resistivity increases with increasing N2 pressure. The observed results are attributed to that N2 pressure can affect the strain and the concentration of Fe–O–Mo, both play important roles in magnetic interaction, and thus affect the magnetic and transport behaviors.