title: Unique spin dynamics and unconventional superconductivity in the layered heavy fermion compound CeIrIn5: NQR evidence.
abstract: We report measurements of the 115In nuclear spin-lattice relaxation rate ( 1/T1) between T = 0.09 and 100 K in the new heavy fermion (HF) compound CeIrIn5. At 0.4 < or = T< or = 100 K, 1/T1 is strongly T-dependent, which indicates that CeIrIn5 is much more itinerant than known Ce-based HFs. We find that 1/T1T, subtracting that for LaIrIn5, follows a (1 / T+straight theta)3/4 variation with straight theta = 8 K. We argue that this novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a magnetic ordering. The bulk superconductivity sets in at 0.40 K below which the coherence peak is absent and 1/T1 follows a T3 variation, which suggests unconventional superconductivity with line-node gap.
authors.affiliation: Department of Physical Science, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Zheng
authors.forename: K
authors.initials: K
authors.lastname: Tanabe
authors.forename: T
authors.initials: T
authors.lastname: Mito
authors.forename: S
authors.initials: S
authors.lastname: Kawasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Kitaoka
authors.forename: D
authors.initials: D
authors.lastname: Aoki
authors.forename: Y
authors.initials: Y
authors.lastname: Haga
authors.forename: Y
authors.initials: Y
authors.lastname: Onuki