Photoconductivity and Percolation of Metallic Clusters in Charge - Ordered
نویسندگان
چکیده
Charge-ordered manganites of composition Pr 1−x (Ca 1−y Sr y) x MnO 3 exhibit persistent pho-toconductivity upon exposure to x-rays. A detailed comparison of the evolution of the conductivity with x-ray illumination and with magnetic field shows that polarization of local spins by x-ray generated hot electrons is predominantly responsible for this effect. As spin-polarized metallic clusters percolate through the charge-ordered background, the transport mechanism changes from tunneling between isolated clusters to ohmic transport along an infinite cluster. Near the percolation threshold, the system is susceptible to instabilities induced by minute injected currents.
منابع مشابه
Persistent X-ray photoconductivity and percolation of metallic clusters in charge-ordered manganites
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