Unique Spin Dynamics and Unconventional Superconductivity in the Layered Heavy Fermion Comp.pdfVIP

Unique Spin Dynamics and Unconventional Superconductivity in the Layered Heavy Fermion Compound CeIrIn : NQR Evidence 5 1 1 1 1 1 2 3 2 G.-q. Zheng , K. Tanabe , T. Mito , S. Kawasaki , Y. Kitaoka , D. Aoki , Y. Haga , and Y. Onuki 1Department of Physical Science, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan 1 2 0 3 Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan 0 Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195, Japan. 2 y 115 We report measurements of the In nuclear spin-lattice relaxation rate (1/T ) between T =0.09 K and 100 K in the new a 1 heavy fermion (HF) compound CeIrIn5 . At 0.4 K ≤ T ≤ 100 K, 1/T1 is strongly T -dependent, which indicates that CeIrIn5 is 3 M much more itinerant than known Ce-based HFs. We find that 1/T T , subtracting that for LaIrIn , follows a ( 1 ) 4 variation 1 5 T +θ 2 with θ=8 K. We argue that this novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a 1 magnetic ordering. The bulk superconductivity sets in at 0.40 K below which the coherence peak i