NMR Investigation of a New Superconductor MoNiP Synthesized under High Pressure.

DOI Web Site Web Site BIBCODE 被引用文献2件 参考文献14件
  • Wada Shinji
    Graduate School of Science and Technology and Faculty of Science, Kobe University,<BR>Nada, Kobe 657-8501
  • Matsuo Tomoyuki
    Graduate School of Science and Technology and Faculty of Science, Kobe University,<BR>Nada, Kobe 657-8501
  • Takata Shohei
    Graduate School of Science and Technology and Faculty of Science, Kobe University,<BR>Nada, Kobe 657-8501
  • Shirotani Ichimin
    Faculty of Engineering, Muroran Institute of Technology, Mizumoto, Muroran 050-8585
  • Sekine Chihiro
    Faculty of Engineering, Muroran Institute of Technology, Mizumoto, Muroran 050-8585

この論文をさがす

説明

95Mo, 61Ni and 31P nuclear magnetic resonance observations in a ternary molybdenum phosphide MoNiP with Fe2P-type structure have been carried out to investigate the mechanism of superconductivity (TC ≅ 8.5 K, HC2 ≅ 7.4 kOe) that appears only when it is synthesized at high pressures. A large negative Knight shift of 95Mo in the superconducting MoNiP, K = -0.155%, is indicative of a dominant d spin core-polarization interaction. The 95Mo spin-lattice relaxation rate, (T1T)-1 = 0.15 (sK)-1, gives a large density of states at the Fermi level, N(EF) ∼ 1.17 states/eV. A positive Knight shift of 61Ni, K = 0.29%, on the other hand, is dominated by the Van Vleck orbital interaction. Thus it is concluded that N(EF) consists mainly of a narrow Mo 4d band. In a non-superconducting MoNiP synthesized at an ambient pressure, K and (T1T)-1 of 95Mo increase to -0.202% and to 0.19 (sK)-1, respectively, indicating that the decrease in N(EF) by ∼ 10% induces the superconductivity, contrary to the prediction of the Bardeen-Cooper-Schrieffer theory. In MoNiP, strong electron correlations in the narrow d band of Mo are thought to be antagonistic to the electron-phonon coupling, VC ∼ Vph, and the synthesis at high pressures provides an additional screening of the Coulomb potential, which leads to the condition of Vph > VC.

収録刊行物

被引用文献 (2)*注記

もっと見る

参考文献 (14)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ