Influence of Ag doping on electrical and magnetic properties of La0.625(Ca0.315Sr0.06)MnO3 ceramics
Influence of Ag doping on electrical and magnetic properties of La0.625(Ca0.315Sr0.06)MnO3 ceramics
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Ag掺杂对La0.625(Ca0.315Sr0.06)MnO3陶瓷电磁性能的影响
DOI：
10.1016/j.ceramint.2017.11.182
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发表时间：
2018-03-01
影响因子：
5.2
通讯作者：
Liu, Xiang
中科院分区：
文献类型：
--
作者：
Jiang, Jun;Zhao, Shuang;Liu, Xiang
采用溶胶-凝胶法制备了多晶ag掺杂[La-0.625(Ca0.315Sr0.06)MnO3](1-x)：分别为（x = 0、0.03、0.05、0.10、0.15和0.20）的Ag-x （LCSMO）陶瓷，并对其结构和性能进行了表征。x射线衍射结果表明，所有样品均为单相正交相（Pbnm空间群），无杂质。随着Ag掺杂量的增加，样品的电阻率降低，剩余磁化强度和矫顽力场增大。x = 0.20时，金属到绝缘子的转变温度（T-p）、电阻温度系数（TCR）和居里温度（T-c）分别为300 K、9.38% （292.6 K）和291.86 K。x = 0.15时MR值最高，为28.36% （295.03 K）。XPS数据表明，a位离子与Ag+之间的取代可以提高Mn4+离子的比例。通过改变Mn-O键距离、Mn-O- mn键角和增加Mn4+离子浓度，增强了双交换效应。这些特征促进了流动电子在Mn3+和Mn4+离子之间的转移。然而，在x = 0.20处获得的磁化强度小于x = 0处，这是由于抗磁性Ag释放了样品的磁性。结果表明，LCSMO多晶陶瓷可作为制备室温红外探测器、磁传感器或磁电器件等的候选材料。
Polycrystalline Ag-doped [La-0.625(Ca0.315Sr0.06)MnO3](1-x):Ag-x (LCSMO) ceramics with (x = 0, 0.03, 0.05, 0.10, 0.15, and 0.20) were prepared by sol-gel method, and their structures and properties were characterized. X-ray diffraction results indicated that all bulk samples had single phase with orthorhombic phase (space group of Pbnm) without impurities. With the increase of Ag doping content, the resistivity of the samples decreased, while the remanent magnetization and coercive field increased. The metal to insulator transition temperature (T-p), temperature coefficient of resistance (TCR) and Curie temperature (T-c) for x = 0.20 were determined as 300 K, 9.38% (292.6 K) and 291.86 K respectively. The highest MR value of 28.36% (295.03 K) was obtained at x = 0.15. XPS data revealed that substitution between A-site ions and Ag+ could increase the ratio of Mn4+ ion. Double exchange effect (DE) enhanced by changing Mn-O bond distance, Mn-O-Mn bond angle, and increasing Mn4+ ion concentration. These features promoted the transfer of itinerant electron between Mn3+ and Mn4+ ions. However, the magnetization obtained at x = 0.20 was less than that at x = 0, as diamagnetic Ag released magnetism of the samples. The results suggested that the LCSMO polycrystalline ceramics could be used as a candidate to prepare room temperature infrared detectors, magnetic sensors or magneto-electric devices, and so on.