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Role of impurity oxygen in superconductivity of "non-doped" T'-(La,RE)2CuO4

A. Tsukada·M. Noda·H. Yamamoto·M. Naito
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Abstract

We have systematically investigated the effect of oxygen nonstoichiometry in a nominally undoped superconductor T'-(La,Y)2CuO4+y. In the experiments, the reduction condition was changed after the sample growth by MBE. The superconductivity is very sensitive to the reduction condition. With systematically increasingly reduced atmospheres, resistivity shows a continuous drop and no discontinuity is observed even until the appearance of superconductivity. The absence of the highly insulating state expected for Mott insulators around y ~ 0 suggests that T'-(La,Y)2CuO4 has intrinsic carriers. The role of residual apical oxygen, which is detrimental to superconductivity, is also discussed based on the resistivity-temperature characteristics in insufficiently reduced samples.

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A. Tsukada, M. Noda, H. Yamamoto, M. Naito. 2005-01-28. Role of impurity oxygen in superconductivity of "non-doped" T'-(La,RE)2CuO4. https://doi.org/10.1016/j.physc.2005.01.034

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