The Effect On Crystal Structures And Properties Of Double Perovskites Ba₂FeMoO₆ By Doping At A Site And O Site

In this paper, double perovskite Ba₂FeMoO_6-xN_x and Ba_2-xK_xFeMoO_6-xF_x series had been successfully synthesized by the solid-state reaction method. The crystal structures and magnetic properties of these samples were characterized by X-ray powder diffraction?XRD? and vibrating sample magnetometer, respectively. The electricity performance of these samples were measured and analyzed using the digital direct electrical bridge method. N content is determined by the Kjeldahl Nitrogen Determination method.The crystal structures of double perovskite Ba₂ Fe MoO_6-xN_x?t = 0, 1, 3, 5, 7, 9 h? series had been successfully synthesized and the diffraction peaks of samples could be indexed in tetragonal system with space group I4/mmm. The lattice volumes decrease with increasing content of N?except 9 h?. The bond angles of Fe-?O, N?- Mo are 180.0 °. The order degree of Fe/Mo demonstrates a decreased tendency with ammonolysis time raised. The saturation magnetization changed with the time of passing ammonia improved. The magnetic moment is not saturated in a 1.0 T magnetic field. The spontaneous magnetization of the samples are reduced as the temperature rise and show a transition from the ferromagnetic to paramagnetic near 380 K, respectively. During the process of analysis electrical performance in this series, we could obtain an obvious negative magnetic resistance effect. From the trend of the resistivity changes with magnetic field rises, all the samples possess obvious negative magnetic resistance effect, which are gradually increase accompany the time passing ammonia. The biggest negative magnetic resistance is 5.8 %?t = 9 h?. Within the temperature range 80 to 450 K, the resistivity of samples Ba₂FeMoO_6-xN_x were increased with increasing temperature in the applied magnetic field?0, 0.5, 1 T?, the behavior which they exhibited belong to typical metal conductor.The crystal structures of double perovskite Ba_2-xK_xFeMoO_6-xF_x(n?K⁺?/(n(Ba²⁺) + n?K⁺?) = N)- Mo are 180.0°. The order degree of Fe/Mo demonstrates an enhanced trend with increasing content of KF. The saturation magnetization changed with the content of KF improved. The magnetic moment is not saturated in a 1.0 T magnetic field. The spontaneous magnetization of the samples are reduced as the temperature rise and show a transition from the ferromagnetic to paramagnetic near 380 K, respectively. During the process of analysis electrical performance in this series, we could obtain an obvious negative magnetic resistance effect. From the trend of the resistivity changes with magnetic field intensity, all the samples possess obvious negative magnetic resistance effect, which are gradually reduced with the content of KF raised. Within the temperature range 80 to 450 K, the resistivity of samples Ba_2-x K_xFeMoO_6-x F_x were increased with increasing temperature in the applied magnetic field?0, 0.5, 1.0 T?, the exhibited behavior of samples belong to typical metal conductor.