Structural Chemistry and Electronic Properties of Sr2FeIrO6

Abstract A polycrystalline sample of Sr 2 FeIrO 6 has been synthesized and shown by a combination of X-ray diffraction, neutron diffraction, magnetometry, and Mossbauer spectroscopy to be a triclinic (space group I 1 ; a =5.54996(3) A, b =5.57847(3) A, c =7.84165(3) A, α =89.990(1)°, β =90.059(1)°, γ =90.079(1)°) perovskite, with a partially ordered (0.928:0.072(4)) distribution of transition metal cations over the six-coordinate sites. The predominant oxidation states are Fe 3+ and Ir 5+ , although the Mossbauer data suggest that ∼4% Fe 4+ is present. The compound is a Type II antiferromagnet below 120 K, with an ordered magnetic moment on the Fe-dominated sites of 3.67(3) μ B per Fe 3+ cation. The spins associated with the antisite defects are frustrated and do not take part in the long-range magnetic ordering, consequently giving rise to hysteresis in the magnetic susceptibility below 40 K. The possible location of the Fe 4+ cations is discussed briefly.