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

Abstract

Charge-ordered manganites of composition $\mathrm{P}{\mathrm{r}}_{1-\mathrm{x}}(\mathrm{C}{\mathrm{a}}_{1-\mathrm{y}}\mathrm{S}{\mathrm{r}}_{\mathrm{y}}{)}_{\mathrm{x}}\mathrm{Mn}{\mathrm{O}}_3$ 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.

arXiv comment8 pages, 4 figures

References in corpus (1)

• Thin-Film Trilayer Manganate Junctions

Cited by in corpus (4)

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• Novel dynamical effects and persistent memory in phase separated manganites
• Multiphase segregation and metal-insulator transition in single crystal La(5/8-y)Pr(y)Ca(3/8)MnO3
• Equilibrium tuned by a magnetic field in phase separated manganite