K. Magishi et al., SPIN CORRELATION IN HIGH-T-C CUPRATE HGBA2CA2CU3O8-C=133 K - AN ORIGIN OF T-C-ENHANCEMENT EVIDENCED BY CU-63-NMR STUDY(DELTA WITH T), Journal of the Physical Society of Japan, 64(12), 1995, pp. 4561-4565
The Knight shift, the nuclear spin-lattice relaxation rate, 1/T-1, and
the transverse relaxation rate, 1/T-20, of (CU)-C-63 have been separa
tely measured for the square and the pyramidal CuO2 planes in HgBa2Ca2
Cu3O8+delta (Hg1223) with the highest transition temperature, T-c = 13
3 K to date. From the quantitative analysis of 1/T-1 and 1/T-2G, it is
shown that the product of the staggered susceptibility and the charac
teristic energy of spin fluctuations around a zone boundary, chi(Q) Ga
mma(Q) for the square CuO2 plane site is larger than that for YBa2Cu3O
7 (YBCO7), although that for the pyramidal CuO2 plane site is almost t
he same. This enhancement of chi(Q) Gamma(Q) for the square site is co
nsidered to be responsible for the higher T-c in Hg1223 than in YBCO7.