1. High-temperature superconductivity and antiferromagnetism in multilayer cuprates: 63Cu and 19F NMR on five-layer Ba2Ca4Cu5O10(F,O)2.
- Author
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Sunao Shimizu, Shin-ichiro Tabata, Shiho Iwai, Hidekazu Mukuda, Yoshio Kitaoka, Shirage, Parasharam M., Hijiri Kito, and Akira Iyo
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HIGH temperature superconductivity , *ANTIFERROMAGNETISM , *COPPER isotopes , *NUCLEAR magnetic resonance spectroscopy , *PHYSICAL measurements , *PHASE diagrams , *MAGNETIC coupling - Abstract
We report systematic Cu and F NMR measurements of five-layered high-Tc, cuprates Ba2Ca4Cu5O10(F,0)2:. It is revealed that antiferromagnetism (AFM) uniformly coexists with superconductivity (SC) in underdoped regions. and that the critical hole density pc for AFM is ∼0.11 in the five-layered compound. We present the layer-number dependence of AFM and SC phase diagrams in hole-doped cuprates, where Pc for AFM is ∼0.11 layered compounds pc (n) increases from pc (l) ∼ 0.02 in La2-xSrxCuO4 or pc (2) ∼ 0.05 in YBa2Cu306+y to pc(5) ∼ 0.11. The variation of pc(n) is attributed to interlayer magnetic coupling, which becomes stronger with increasing n. In addition, we focus on the ground-state phase diagram of CuO2 planes, where AFM metallic states in slightly doped Mott insulators change into the uniformly mixed phase of AFM and SC and into simple rf-wave SC states. The maximum Tc exists just outside the quantum critical hole density, at which AFM moments on a CuO2 plane collapse at the ground state, indicating an intimate relationship between AFM and SC. These characteristics of the ground state are accounted for by the Mott physics based on the t-J model; the attractive interaction of high-Tc SC, which raises Tc as high as 160 K, is an in-plane superexchange interaction Jin (∼0.12 eV), and the large Jm binds electrons of opposite spins between neighboring sites. It is the Coulomb repulsive interaction U (>6 eV) between Cu-3
- Published
- 2012
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