^<29>Si NMR Study of Antiferromagnetic Superconductor URu_2Si_2

概要

論文の詳細を見る
We present "81 NMR spectra, nuclear spin-lattice relaxation time, 'Z'l, and nuclear spin echodecav time, V'2, meastrrements in URuzSix over the temr>erature ranue from 0.15 K to 300 K.I/T3 obtained with c-axis perpendicular to the external field H..(, l/TIL, is much larger thanthat obtained with c-axis rarallel to #e.t., l./Tnj. Existence of large anisotror>v of X/Tn touetherwith the nearly isotropic "Si hyperfine field imply that the spin fluctttations exist predominantlyin the direction of the tetragonal c-axis. The temperature, T , dependence of I/T)@,77 is nearly]-independent above 60 K and is proportional to T at low temperatures, which indicates thecrossover from the localized state at high ternperatures to the Fermi liqtrid state below about60 K occurs in the electronic state of 5f electrons. l/V'l and l/'Z'2 decrease markedly belowT?=17.5 K associated with the antiferrornagnetic order. Below T0, I/T) has no coherencepeak and decreases proportionally to T' at low temperatures, which is well described in termof an anisotropic strperconducting energy gap model with line nodes. Although the decrease ofKnight shift was expected in spin-singlet strperconductor mediated by antiferromagnetic electron-electron coupling znechanism, no decrease of "Si Knight shift was detected within experimentalerrors.
社団法人日本物理学会の論文
1996-04-15