Magnetic and transport properties of the double perovskite Sr2FeRuO6

The doubleperovskite Sr2FeRuO6 has been synthesized by the solid-state reaction method. X-ray diffraction and subsequent Rietveld refinement confirm that Sr2FeRuO6 has the doubleperovskite structure with a triclinic cell (a=5.508 Å, b=5.474 Å, c=7.861 Å, β=90.127) and space group I2/c. Due to the absence of the superlattice reflections (1 1 1) and (3 1 1), Fe and Ru atoms are found to occupy the center of the oxygen octahedron (B-sites) randomly. The magnetization curve at 300 K has been measured up to 90,000 Oe and reveals a very small magnetic susceptibility (χ=2.99×10−6 emu/g). Due to the disorder of Fe and Ru ions at the B-sites, Sr2FeRuO6 is supposed to exhibit spin-glass behavior at low temperatures, instead of a long-range magnetic ordering state. The temperature dependence of the electrical resistivity has been measured at 0–70,000 Oe and indicates that Sr2FeRuO6 is a typical semiconductor with an energy gap of about 0.23 eV. At 70,000 Oe and 115 K, the magnetoresistance (MR) is as large as about 25%.