Magnetic-field-induced enhancement of nuclear spin-lattice relaxation rates in the heavy-fermion superconductor CeCoIn using Co nuclear magnetic resonance

Sakai, Hironori   ; Brown, S. E.*; Baek, S.-H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Co nuclear spin lattice relaxation has been measured for the heavy-fermion superconductor CeCoIn in a range of applied fields directed parallel to the -axis. An enhanced normal state relaxation rate, observed at low temperatures and fields just above , is taken as a direct measure of the dynamical susceptibility and provides microscopic evidence for an antiferromagnetic instability. The results are well-described using the self-consistent renormalized theory for two-dimensional antiferromagnetic spin fluctuations, and parameters obtained in the analysis are applied to previously reported specific heat and thermal expansion data with good agreement.