Synthesis, crystal structure, and physical properties of Sr ₂FeOsO₆

In the exploration of new osmium based double perovskites, Sr ₂FeOsO₆ is a new insertion in the existing family. The polycrystalline compound has been prepared by solid state synthesis from the respective binary oxides. Powder X-ray diffraction (PXRD) analysis shows the structure is pseudocubic at room temperature, whereas low-temperature synchrotron data refinements reveal the structure to be tetragonal, space group I4/m. Heat capacity and magnetic measurements of Sr₂FeOsO₆ indicated the presence of two magnetic phase transitions at T₁ = 140 K and T₂ = 67 K. Band structure calculations showed the compound as a narrow energy gap semiconductor, which supports the experimental results obtained from the resistivity measurements. The present study documents significant structural and electronic effects of substituting Fe³⁺ for Cr³⁺ ion in Sr₂CrOsO₆.