Structural and electrical properties of La2-xSrxMo2O9-δ
来源期刊：JOURNAL OF RARE EARTHS2013年第4期
论文作者：闫柏军 李明 张家芸
文章页码：428 - 434
摘 要：Sr-doped La2Mo2O9 were prepared by solid state reaction and characterized by XRD,impedance spectroscopy and HebbWagner polarization method.XRD patterns of the samples indicated that the solubility limit of Sr2+ in La2-xSrxMo2O9-δ was in the range of 7 mol.% to 7.5 mol.%,i.e.,the maximum stoichiometric coefficient x in La2-xSrxMo2O9-δ was larger than 0.14 and less than 0.15.The cubic lattice parameter of La2-xSrxMo2O9-δ（0<x≤0.14） increased linearly with the content of dopant Sr 2+ increasing and the relationship could be expressed as:a=0.7154+0.00451x（mm）.The total conductivities of Sr-doped La2Mo2O9 were measured by impedance spectroscopy method in argon and air atmosphere,respectively.The results indicated that substituting Sr2+ for La3+ could suppress the first order phase transform of La2Mo2O9 and stabilize the cubic structure to room temperature,and the conductivities of Sr-doped La2Mo2O9 were more sensitive to the change of atmosphere than that of undoped La2Mo2O 9.The conductivity variation of Sr-doped La2Mo2O9 with the dopant content exhibited similar trend in air and argon atmosphere,firstly decreased and then increased with the dopant content increasing,and a minimum value appeared at x=0.1.The electronic conductivities of Sr-doped La2Mo2O9 were measured using Hebb-Wagner polarization method in argon atmosphere.It could be found that Sr-doping caused the increase in electronic conductivity and decrease in oxide-ion transport numbers,but the conducting species were predominantly oxide ions.And the oxide-ion transport numbers of some Sr-doped La2Mo2O9 samples could also reach 0.99.
闫柏军，李明，张家芸
State Key Laboratory of Advanced Metallurgy,School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing
摘 要：Sr-doped La2Mo2O9 were prepared by solid state reaction and characterized by XRD,impedance spectroscopy and HebbWagner polarization method.XRD patterns of the samples indicated that the solubility limit of Sr2+ in La2-xSrxMo2O9-δ was in the range of 7 mol.% to 7.5 mol.%,i.e.,the maximum stoichiometric coefficient x in La2-xSrxMo2O9-δ was larger than 0.14 and less than 0.15.The cubic lattice parameter of La2-xSrxMo2O9-δ（0<x≤0.14） increased linearly with the content of dopant Sr 2+ increasing and the relationship could be expressed as:a=0.7154+0.00451x（mm）.The total conductivities of Sr-doped La2Mo2O9 were measured by impedance spectroscopy method in argon and air atmosphere,respectively.The results indicated that substituting Sr2+ for La3+ could suppress the first order phase transform of La2Mo2O9 and stabilize the cubic structure to room temperature,and the conductivities of Sr-doped La2Mo2O9 were more sensitive to the change of atmosphere than that of undoped La2Mo2O 9.The conductivity variation of Sr-doped La2Mo2O9 with the dopant content exhibited similar trend in air and argon atmosphere,firstly decreased and then increased with the dopant content increasing,and a minimum value appeared at x=0.1.The electronic conductivities of Sr-doped La2Mo2O9 were measured using Hebb-Wagner polarization method in argon atmosphere.It could be found that Sr-doping caused the increase in electronic conductivity and decrease in oxide-ion transport numbers,but the conducting species were predominantly oxide ions.And the oxide-ion transport numbers of some Sr-doped La2Mo2O9 samples could also reach 0.99.
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