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NMR evidence for two-step phase-separation in Nd_{1.85}Ce_{0.15}CuO_{4-delta}

O. N. Bakharev·I. M. Abu-Shiekah·H. B. Brom·A. A. Nugroho·I. P. McCulloch·J. Zaanen
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Abstract

By Cu NMR we studied the spin and charge structure in Nd_{2-x}Ce_{x}CuO_{4-delta}. For x=0.15, starting from a superconducting sample, the low temperature magnetic order in the sample reoxygenated under 1 bar oxygen at 900^0 C, reveals a peculiar modulation of the internal field, indicative for a phase characterized by large charge droplets ('Blob'-phase). By prolonged reoxygenation at 4 bar the blobs brake up and the spin structure changes to that of an ordered antiferromagnet (AF). We conclude that the superconductivity in the n-type systems competes with a genuine type I Mott-insulating state.

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O. N. Bakharev, I. M. Abu-Shiekah, H. B. Brom, A. A. Nugroho, I. P. McCulloch, J. Zaanen. 2004-05-19. NMR evidence for two-step phase-separation in Nd_{1.85}Ce_{0.15}CuO_{4-delta}. https://doi.org/10.1103/physrevlett.93.037002

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