Persistent X-ray photoconductivity and percolation of metallic clusters in charge-ordered manganites
Persistent X-ray photoconductivity and percolation of metallic clusters in charge-ordered manganites
复制标题
电荷有序锰酸盐中金属团簇的持久 X 射线光电导和渗流
DOI：
10.1209/epl/i1999-00356-y
复制
发表时间：
1998
期刊：
影响因子：
1.8
通讯作者：
Y. Tokura
中科院分区：
文献类型：
--
作者：
D. Casa;V. Kiryukhin;O. Saleh;B. Keimer;J. Hill;Y. Tomioka;Y. Tokura
组成为Pr 1 − x（Ca 1 − ySry）xMnO 3的电荷有序锰氧化物在暴露于X射线时表现出持久的光电导性。这并不总是伴随着一个显着增加的传导电子的数量所预测的持久性光电导的传统模型。的X射线衍射图案和电流-电压特性的分析表明，X射线照射的结果在微观上相分离的状态，其中电荷有序的绝缘区域提供对金属簇之间的电荷传输的障碍。X射线照射的主要作用是通过降低或去除这些势垒来提高电子迁移率。提出了一种基于磁自由度的机构。
Charge-ordered manganites of composition Pr1 − x(Ca1 − ySry)xMnO3 exhibit persistent photoconductivity upon exposure to X-rays. This is not always accompanied by a significant increase in the number of conduction electrons as predicted by conventional models of persistent photoconductivity. An analysis of the X-ray diffraction patterns and current-voltage characteristics shows that X-ray illumination results in a microscopically phase-separated state in which charge-ordered insulating regions provide barriers against charge transport between metallic clusters. The dominant effect of X-ray illumination is to enhance the electron mobility by lowering or removing these barriers. A mechanism based on magnetic degrees of freedom is proposed.