研究了在钙钛矿结构 Sr2 Fe Mo O6 陶瓷中存在的多种不同的有序晶格结构 .如 Fe- Mo离子在简单钙钛矿结构 ABO3中的 B位无序分布 ;Fe- Mo B位空间排列的 Na Cl型有序分布的钙钛矿结构及在 c轴方向具有 3倍简单钙钛矿结构周期的层状超结...研究了在钙钛矿结构 Sr2 Fe Mo O6 陶瓷中存在的多种不同的有序晶格结构 .如 Fe- Mo离子在简单钙钛矿结构 ABO3中的 B位无序分布 ;Fe- Mo B位空间排列的 Na Cl型有序分布的钙钛矿结构及在 c轴方向具有 3倍简单钙钛矿结构周期的层状超结构等 .结果表明 ,通过正确选择 Sr2 Fe Mo O6 陶瓷材料的微结构 。展开更多
A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits ...A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.展开更多
The structure, magnetic and electric properties of Sr2FeMoO6 (the as-made sample) and samples after heat treatment were investigated. The nuclear and magnetic structures of the samples were studied using neutron powde...The structure, magnetic and electric properties of Sr2FeMoO6 (the as-made sample) and samples after heat treatment were investigated. The nuclear and magnetic structures of the samples were studied using neutron powder diffraction at room temperature. The results show that the tunneling magnetoresistance of polycrystalline Sr2FeMoO6 depends on its annealing temperature. Annealing at 800 ℃ makes the minimal magnetoresistance(MR) elevated, which may be due to the change of the grain size or the modified intergranular connections. Because of the impurity phase of Fe which probably affects the magnetotransport properties is much larger in sample C, so the MR is decreased by postannealing at 1100 ℃. Therefore, further enhancement of the tunneling magnetoresistance (TMR) can be realized by regulating the grain size at appropriate annealing temperature.展开更多
文摘研究了在钙钛矿结构 Sr2 Fe Mo O6 陶瓷中存在的多种不同的有序晶格结构 .如 Fe- Mo离子在简单钙钛矿结构 ABO3中的 B位无序分布 ;Fe- Mo B位空间排列的 Na Cl型有序分布的钙钛矿结构及在 c轴方向具有 3倍简单钙钛矿结构周期的层状超结构等 .结果表明 ,通过正确选择 Sr2 Fe Mo O6 陶瓷材料的微结构 。
基金Supported by the National Natural Science Foundation of China under Grant No U1304110the Doctoral Science Foundation of Henan Normal University under Grant No 01026500109
文摘A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.
基金Project(1998061304) supported by the National Natural Foundation of China
文摘The structure, magnetic and electric properties of Sr2FeMoO6 (the as-made sample) and samples after heat treatment were investigated. The nuclear and magnetic structures of the samples were studied using neutron powder diffraction at room temperature. The results show that the tunneling magnetoresistance of polycrystalline Sr2FeMoO6 depends on its annealing temperature. Annealing at 800 ℃ makes the minimal magnetoresistance(MR) elevated, which may be due to the change of the grain size or the modified intergranular connections. Because of the impurity phase of Fe which probably affects the magnetotransport properties is much larger in sample C, so the MR is decreased by postannealing at 1100 ℃. Therefore, further enhancement of the tunneling magnetoresistance (TMR) can be realized by regulating the grain size at appropriate annealing temperature.
