  In the exploration of new osmium based double perovskites, Sr2FeOsO6 is a new
insertion in the existing family. The polycrystalline compound has been
prepared by solid state synthesis from the respective binary oxides. PXRD
analysis shows the structure is pseudo-cubic 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.
