Crystallographic and Magnetic Properties of Double Perovskite Oxide Ba2-xSrxFeMoO6

In order to study on the change of magnetic properties according to the tolerance factor, polycrystalline single phase double perovskite oxide Ba2-xSrxFeMoO6 (x = 0.0, 0.5, 1.0, 1.5, 2.0) are prepared. The crystallographic and magnetic properties have been studied by X-ray diffraction, magnetization measurements and Mossbauer spectroscopy. The Ba2FeMoO6 is analyzed as a cubic structure with Fe3+ and Mo5+ ions ordered at the B-sites. As the x value increases from the cubic structure, the lattice constant decreases more rapidly in the a-b-axis direction than in the c-axis. So that the tetragonal structure starts from x = 1.0. The Curie temperature of the Ba2FeMoO6 and Sr2FeMoO6 were 345 K and 425 K, respectively. As the value of x increases, the Curie temperature increases linearly. In addition, the magnetic hyperfine field fluctuation due to relaxation effects are observed in the Mossbauer spectrum of all series samples.