论文标题
玻璃介电异常和电子掺杂的磁电气含量ca $ _ {1-x} $ sr $ _x $ _x $ _x $ _ {0.85} $ sb $ _ {0.15} $ _ {0.15}
Glassy dielectric anomaly and negative magneto-capacitance effect in electron-doped Ca$_{1-x}$Sr$_x$Mn$_{0.85}$Sb$_{0.15}$O$_3$
论文作者
论文摘要
锰岩具有各种类型的电子现象，这些电子特性可以通过载体掺杂来控制。在此，我们报告了电子掺杂的锰矿的介电和磁性ca $ _ {1-x} $ sr $ _x $ _x $ mn $ _ {0.85} $ sb $ _ {0.15} $ o $ $ $ $ $ _3 $（$ x $ = 0、0.1、0.2、0.2和0.3）。介电常数的实际部分的温度依赖性在磁化的扭结温度以下表现出宽和大峰，并且在较低温度下急剧降低，并伴有假想部分的异常。此外，Isovalent SR替换可将介电峰的温度升高超过50K。有趣的是，介电峰表现出负磁场效应。对于所有测得的样品，可以根据麦克斯韦 - 瓦格纳（MW）模型定性地解释介电常数的低温变化，该模型描述了由晶界和半导体晶粒组成的系统。然而，在高温下观察到的峰及其负磁电气效应不能通过MW模型和磁场效应的组合来重现。介电峰强烈表明当前系统中的二极管松弛。这些结果表明，极性子形成偶极顺序和磁电耦合的簇，这可以通过电荷订购场景一致地理解。
Manganites exhibit various types of electronic phenomena, and these electronic characteristics can be controlled by carrier doping. Herein, we report the dielectric and magnetic properties of electron-doped manganite Ca$_{1-x}$Sr$_x$Mn$_{0.85}$Sb$_{0.15}$O$_3$ ($x$ = 0, 0.1, 0.2, and 0.3). The temperature dependence of the real part of the dielectric constant exhibits a broad and large peak just below the kink temperature of magnetization and a sharp decrease at lower temperatures, accompanied by an anomaly of the imaginary part. Furthermore, isovalent Sr substitution enhances the temperature of the dielectric peak by more than 50 K. Interestingly, the dielectric peak exhibits a negative magnetic-field effect. For all measured samples, the low-temperature variation of the dielectric constant can be qualitatively explained based on the Maxwell-Wagner (MW) model that describes a system composed of grain boundaries and semiconducting grains. However, the observed peak and its negative magneto-capacitance effect at high temperatures cannot be reproduced by a combination of the MW model and magnetoresistance effect. The dielectric peak strongly indicates polaronic relaxation in the present system. These results suggest that polarons form clusters with a dipole ordering and magneto-electric coupling, which might be consistently understood by the charge-ordering scenario.
