Observation of room-temperature spontaneous chemical phase segregation in overdoped Bi2Sr2CaCu2O8+x single crystals

Article

关键词: MAGNETIC-SUSCEPTIBILITY;    CRITICAL FLUCTUATIONS;    OXYGEN DIFFUSION;    SEPARATION;    LA2CUO4+DELTA;    SUPERCONDUCTIVITY;   

DOI  :  10.1103/PhysRevB.66.134506

来源: SCIE

【 摘 要 】

The occurrence and development of phase inhomogeneity in Bi2Sr2CaCu2O8+x single crystals have been investigated by measuring their superconducting transition patterns using a high-sensitivity ac magnetometer. We find that the overdoped Bi2Sr2CaCu2O8+x single crystals, even if they were single-phased immediately after a high-temperature annealing process, show progressively pronounced multiple superconducting transitions with time as they were kept at room temperature in a dry air atmosphere. The results reveal that the oxygen dopants in the crystal are still mobile at room temperature. These dopants tend to rearrange and thus form different phases, at a characteristic time scale of one or two weeks or so. Moreover, the diamagnetic loops in the newly segregated phase are very weak, presumably due to the existence of additional inhomogeneity down to a nanometer scale. Our results also show that the optimally doped Bi2Sr2CaCu2O8+x crystals seem capable to remain in a single transition with storage time.

【 授权许可】

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