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Persistent X-Ray Photoconductivity and Percolation of Metallic Clusters in Charge-Ordered Manganites

D. Casa·V. Kiryukhin·O. A. Saleh·B. Keimer·J. P. Hill·Y. Tomioka·Y. Tokura
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Abstract

Charge-ordered manganites of composition $\rm Pr_{1-x}(Ca_{1-y}Sr_{y})_{x}MnO_3$ exhibit persistent photoconductivity upon exposure to x-rays. This is not always accompanied by a significant increase in the {\it 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 {\it mobility} by lowering or removing these barriers. A mechanism based on magnetic degrees of freedom is proposed.

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D. Casa, V. Kiryukhin, O. A. Saleh, B. Keimer, J. P. Hill, Y. Tomioka, Y. Tokura. 1999-09-01. Persistent X-Ray Photoconductivity and Percolation of Metallic Clusters in Charge-Ordered Manganites. https://doi.org/10.1209/epl%2Fi1999-00356-y

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