| In this paper, double perovskite Sr2FeMoO6-xNxand Sr2-xLaxFeMoO6-xNxseries had beensuccessfully synthesized by solid-state reaction method. The crystal structures and magneticproperties of these samples were researched by X ray powder diffraction (XRD) andvibrating sample magnetometer, respectively. N content is determined by the formaldehydemethod.The crystal structures of double perovskite Sr2FeMoO6-xNx(t=0,1,4,6,9and12h)series had been successfully synthesized all belong to tetragonal system. The space groups ofthese samples are all I4/mmm. The lattice volumes decrease with increasing content of N. Theaverage bond lengths of Fe (O,N) and Mo (O,N) decrease with Fe and Mo contentincreasing, respectively, except that of ammonolysis6h. The bond angles of Fe (O,N) Moare all near180.0°. The bond-valence for Sr is close to+2. The bond-valence for Modemonstrates an increase with ammonolysis time. The bond-valence for Fe demonstrates adecrease with ammonolysis time, except that of ammonolysis4h. The degree of orderdemonstrates an increase with ammonolysis time. The fitting of M-T curves indicates that inlow temperature range the spontaneous magnetization follows spin-wave theory and in hightemperature region almost obeys spin wave model. B obtained from low temperature increaseat first and then decrease with ammonolysis time, except that of ammonolysis9h. B obtainedfrom high temperature decrease with ammonolysis time. The spontaneous magnetizationdecrease firstly and then increase with ammonolysis time. The magnetic moment is notsaturated in a1.0T magnetic field in the M H curve. The saturation magnetization increase atfirst and then decrease with the increasing content of N at300and78K, respectively.The crystal structures of double perovskite Sr2-xLaxFeMoO6-xNx(t=1,4,6,9and12h)series had been successfully synthesized all belong to monoclinic system. The space groups ofthese samples are all P21/n. The lattice volumes increase with ammonolysis time (increasingcontent of La). The average bond lengths of Fe (O,N) and Mo (O,N) increase with Fe andMo content increasing, respectively, except that of ammonolysis9h. The bond angles of Fe (O,N) Mo decrease with increasing content of N(La), except that of ammonolysis9h.respectively. The average bond-valence for Sr and La is larger than+2. The bond-valence forFe is larger than+3. The bond-valence for Mo is smaller than+5. The degree of orderdemonstrates a decrease with ammonolysis time (increasing content of La). The fitting ofM T curves indicates that both in low temperature region and in high temperature region thespontaneous magnetization follows spin-wave theory. B obtained from low temperatureandand high temperature increase with ammonolysis time (increasing content of La). Thespontaneous magnetization decreases with ammonolysis time (increasing content of La). Themagnetic moment is not saturated in a1.0T magnetic field in the M H curve. The saturationmagnetization decrease with the increasing content of N (the increasing content of La) at300and78K, respectively. |
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