NMR study of the Peculiar Superconducting Mixed State in the Np Superconductor

• Project/Area Number: 21740273
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics II
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: CHUDO Hiroyuki 独立行政法人日本原子力研究開発機構, 先端基礎研究センター, 任期付研究員 (30455282)
• Project Period (FY): 2009 – 2011
• Project Status: Completed (Fiscal Year 2011)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2011: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2010: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2009: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 核磁気共鳴 / 交差緩和 / 重い電子超伝導体 / アクチノイド化合物 / 超伝導混合状態 / ネプツニウム化合物 / 超伝導

Research Abstract

A^^<27> l nuclearspin-lattice relaxation rate 1/T^^<27>_1 has been measured in heavy fermion superconductor NpPd_5Al_2 for a wide range of external fields between 0.7 and 11T. We found that 1/T^^<27>_1 exhibits a strong, fields-dependence behavior at low field s below H^～ 3T, which is attributed to unlike-spin cross relaxation between N^^<237> p-A^^<27> l. An analysis based on the cross relaxation process allows us to make the first quantitative estimation of the Np nuclear relaxation rate 1/^<237>τin an itinerant 5f electron system. The estimated values of 1/^<237>τ^～ 6×10^7 s^<-1>, with a weak temperature variation, are below the resolution of NMR relaxation time, indicating that a direct observation of the N^^<237> p NMR signal would be very difficult, at least in the paramagnetic state. It is proposed that a direct observation of N^^<237> p NMR might be possible in the superconducting state at T^～ 1K.

Research Products

• [Journal Article] Observation of P^^<239> u Nuclear Magnetic Resonance (2012)
  • Author(s): H. Yasuoka, G. Koutroulakis, H. Chudo, S. Richmond, D. K. Veirs, A. I. Smith, E. D. Bauer, J. D. Thompson, G. D. Jarvinen, D. L. Clark
  • Journal Title: Science Volume: Vol.336 Issue: 6083 Pages: 901-904
  • DOI: 10.1126/science.1220801
  • Peer Reviewed
• [Journal Article] ^<237>Np nuclear relaxation rate in heavy fermion superconductor NpPd_5Al_2 (2011)
  • Author(s): H.Chudo, Y.Tokunaga, et al
  • Journal Title: Phys.Rev.B Volume: 84 Issue: 9 Pages: 94-402
  • DOI: 10.1103/physrevb.84.094402
  • Peer Reviewed
• [Journal Article] Anisotropic Spin Fluctuations in Heavy-Fermion Superconductor NpPd_5Al_2 (2010)
  • Author(s): H. Chudo, H. Sakai, Y. Tokunaga, S. Kambe, D. Aoki, Y. Homma, Y. Haga, T. D. Matsuda, Y. nuki, H. Yasuoka
  • Journal Title: Journal of the Physical Society of Japan Volume: Vol.79
  • Peer Reviewed
• [Journal Article] P^<105> dNQR Study on NpPd_5Al_2 and CePd_5Al_2 (2010)
  • Author(s): H. Chudo, H. Sakai, Y. Tokunaga, S. Kambe, D. Aoki, Y. Haga, T. D. Matsuda, Y. Homma, Y. Nakano, F. Honda, R. Settai, Y. nuki, H. Yasuoka
  • Journal Title: Journal of Physics : Conference Series Volume: Vol.200 Issue: 1 Pages: 012020-012020
  • DOI: 10.1088/1742-6596/200/1/012020
  • Peer Reviewed
• [Journal Article] Anisotropic Spin Fluctuations in Heavy-Fermion Superconductor NpPd_5Al_2 (2010)
  • Author(s): H.Chudo et al.
  • Journal Title: J.Phys.Soc.Jpn. 79
  • Peer Reviewed
• [Journal Article] ^<105>Pd NQR Study on NpPd_5Al_2 and CePd_5Al_2 (2010)
  • Author(s): H.Chudo et al.
  • Journal Title: J.Phys.:Conf.Ser. 200
  • Peer Reviewed
• [Journal Article] Evidence for Appearance of an Internal Field in the Ordered State of CeRu_2Al_<10> by μ^+SR (2010)
  • Author(s): S.Kambe et al.
  • Journal Title: J.Phys.Soc.Jpn. 79
  • Peer Reviewed
• [Journal Article] One-Component Description of Magnetic Excitations in the Heavy-Fermion Compound CeIrIn_5 (2010)
  • Author(s): S.Kambe et al.
  • Journal Title: Phys.Rev.B 81 Pages: 140405-140405
  • Peer Reviewed
• [Journal Article] ^<17>O NMR Study in(Pu_<0.91>Am_<0.09>)O_2 (2010)
  • Author(s): Y.Tokunaga et al.
  • Journal Title: J.Nucl.Mate. 396 Pages: 107-111
  • Peer Reviewed
• [Journal Article] NMR Evidence for the 8.5K Phase Transition in Americium Dioxide (2010)
  • Author(s): Y.Tokunaga et al.
  • Journal Title: J.Phys.Soc.Jpn. 79
  • Peer Reviewed
• [Presentation] Np^^<273> Nuclear Relaxation rate in Heavy Fermion Superconductor NpPd_5Al_2 (2011)
  • Author(s): 中堂博之
  • Organizer: 新学術領域研究「重い電子系の形成と秩序化」第三回研究会
  • Place of Presentation: 千葉県
  • Year and Date: 2011-06-24
• [Presentation] ^<237>Np nuclear relaxation rate in heavy fermion superconductor NpPd_5Al_2 (2011)
  • Author(s): H.Chudo
  • Organizer: 重い電子系の形成と秩序化第3回研究会
  • Place of Presentation: 東大物性研究所
  • Year and Date: 2011-06-24
• [Presentation] NpPd_5Al_2におけるスピン揺らぎの異方性と超伝導 (2010)
  • Author(s): 中堂博之
  • Organizer: 日本物理学会2010年秋季大会
  • Place of Presentation: 大阪府
  • Year and Date: 2010-09-25
• [Presentation] NpPd_5Al_2におけるスピン揺らぎの異方性と超伝導 (2010)
  • Author(s): 中堂博之
  • Organizer: 日本物理学会2010年秋季大会
  • Place of Presentation: 大阪府立大学
  • Year and Date: 2010-09-25
• [Presentation] ネプツニウム化合物超伝導体NpPd_5Al_2の^<27>Al NMRによる研究VI (2010)
  • Author(s): 中堂博之
  • Organizer: 日本物理学会2010年第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-21
• [Presentation] ネプツニウム化合物超伝導体NpPd_5Al_2の^<27>Al NMRによる研究V (2009)
  • Author(s): 中堂博之
  • Organizer: 日本物理学会2009年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-27
• [Presentation] Anisotropic Spin Fluctuations in NpPd_5Al_2 (2009)
  • Author(s): 中堂博之
  • Organizer: Novel Spin Paring(NSP '09)
  • Place of Presentation: Kyoto, Japan
  • Year and Date: 2009-09-14
• [Presentation] Anisotropic Spin Fluctuations in NpPd_5Al_2 (2009)
  • Author(s): 中堂博之
  • Organizer: International Conference on Magnetism(ICM '09)
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2009-07-30