Local moments in the heterogeneous electronic state of Cd-substituted CeCoIn5: NQR relaxation rates

International Conference on Strongly Correlated Electron Systems 2016

Sakai, H.^1 ; Ronning, F.^2 ; Hattori, T.^1 ; Tokunaga, Y.^1 ; Kambe, S.^1 ; Zhu, J.-X.^3 ; Wakeham, N.^2 ; Yasuoka, H.^2 ; Bauer, E.D.^2 ; Thompson, J.D.^2

Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki, Tokai

319-1195, Japan^1

Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos

NM

87545, United States^2

Theoretical Division, Los Alamos National Laboratory, Los Alamos

NM

87545, United States^3

关键词: Bulk electronic state;    Close proximity;    Nuclear spin relaxation rate;    Quantum critical;    Relaxation rates;    Spin echo decay rate;    Temperature dependence;    Transverse nuclear spin relaxation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/807/3/032001/pdf
DOI  :  10.1088/1742-6596/807/3/032001

来源: IOP

【 摘 要 】

We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum critical metal CeCoIn5to substitutions of small amounts of Cd for In. Approximately half of the Cd substituents induce local Ce moments in their close proximity, as observed by site-dependent longitudinal nuclear spin relaxation rates 1/T1. To reaffirm that localized f moments are induced around the Cd substituents, we find a Gaussian spin-echo decay rate 1/T2Gof transverse nuclear spin relaxation. Further, for the NQR subpeak is found to be proportional to temperatures, again indicating local moments fluctuations around the Cd substituents, while that for the NQR main peak shows a T0.7-dependence. The latter temperature dependence is close to 0.75 in pure CeCoIn5and indicates that the bulk electronic state is located close to a two dimensional quantum critical instability.