New and Non-Cuprate SuperconductorsNo Access

NMR STUDIES OF LAYERED NITRIDE SUPERCONDUCTORS

Department of Quantum matters, AdSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan

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MASAFUMI SERA

Department of Quantum matters, AdSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan

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YUTAKA MANIWA

Department of Physics, Graduate school of Science, Tokyo Metropolitan University, Hachi-oji, Tokyo 192-0397, Japan

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SHOJI YAMANAKA

Department of Applied Chemistry, Graduate school of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan

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https://doi.org/10.1142/S0217979207044512Cited by:4 (Source: Crossref)

Abstract

Layered nitride superconductor, Li_0.48(THF)_yHfNCl with Tc=25.5 K, was investigated by means of nuclear magnetic resonance (NMR). ⁷Li-, ³⁵Cl-NMR studies clarified that the partial electron density of states at Fermi level at Li and Cl sites are negligibly small. From the ¹⁵N NMR Knight shift studies, the spin susceptibility decreases toward zero below T_c, evidencing that the pairing symmetry is an even-parity spin-singlet. These results indicate that superconductivity is derived from the HfN layer. We also measured ¹⁵N-, ⁷Li-NMR spin-lattice relaxation rate in the temperature range of 4.2K - 100 K and observed the enhancement of the spin-lattice relaxation rate, 1/T₁, by field fluctuations generated by the vortex dynamics.