Measurements of the nuclear quadrupole resonance (NQR) transverse relaxatio
n rate of (CU)-C-63,65 and of the NQR linewidths in YBa2CU3O7-delta in the
superconducting state reveal unusual features below T = 35 K. A narrow peak
in the transverse relaxation rate and an increased quadrupolar line broade
ning with decreasing temperature are attributed to a charge density wave or
dered state below T = 35 K.