NQR STUDY IN YBA2CU4O8 UNDER HIGH-PRESSURE

The temperature dependence of the (CU)-C-63 nuclear spin-lattice relax ation rate (T1T)(-1) and spin-spin relaxation rate T-2G(-1) at the CU( 2) planar site in the normal state of YBa2Cu4O8 have been measured und er high pressure by the nuclear quadrupole resonance (NQR) technique. T-1(-1) and T-2G(-1) could be fitted by single exponential and Gaussia n at all temperatures, respectively. It seems that the pseudo-spin gap temperature at 1GPa which was determined by the T-dependence of (T1T) (-1) slightly decreased compared with at ambient pressure. (C) 1998 El sevier Science B.V. All rights reserved.