CU-63/65/TL-203/205 NMR STUDY ON THE ANTIFERROMAGNETIC PHASE OF THE TL-BASED HIGH-T-C OXIDE TLBA2YCU2O7

摘要

The end member of the T1-based high-T-c cuprate TIBa2YCu2O7 (Tl1212) with the zero nominal hole number has been synthesized and studied by Cu/Tl NMR. The existence of the antiferromagnetic ordering was demonstrated by the Zeeman-splitted zero-field Cu spectra. Static parameters at the Cu site such as the hyperfine field H-Cu=8.62 T and the quadrupolar frequency (63)v(Q)=20.44 MHz were found to be comparable to other high-T-c related antiferromagnets La2CuO4 and YBa2Cu3O6. The relaxation rate T-l(-1) of the Cu site of Tl1212 showed a significant deviation from the magnon theory, and was much smaller than La2CuO4 and YBa2Cu3O6. The scaling between the temperature dependence of Tl T-l(-1) and Cu T-l(-1), the ratio of which was consistently explained with tile hyperfine coupling constants determined by the analysis of spectra, showed that the relaxation is dominated by the 3d spin fluctuation. A possible relation between the spin fluctuation in the antiferromagnetic phase and the superconductivity in the high-T-c phase is also stated. [References: 36]