NMR Studies of Superconductivity and Metal-Insulator Transition in Cu Spinel CuM2X4 (M = Rh, Ir and X = S, Se)
作者： K. Kumagai , S. Tsuji , T. Hagino , S. Nagata
DOI: 10.1007/978-3-642-57834-2_23
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摘要: Electronic and magnetic properties of spinel compounds CuRh2S4, CuRh2Se4 CuIr2S4 are investigated by 63Cu-NMR. CURh22S4 superconductors with T c=3−5K. Metal-insulator transition (MIT) occurs at 230K in CuIr2S4. Knight shift, K, nuclear spin-lattice relaxation time, 1, change largely MTT, indicating that the spin density Cu site decreases owing to opening band gap insulating state. The NMR results support valence state is basically nonmagnetic below MIT. appearance coherence peak 1/T 1 just c exponential behavior temperature CuRh2S4 suggest superconducting nature spinels interpreted qualitatively within BCS picture.
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