Evidence for Ba-site occupation of Pr3+ in Y1-xPrBa2Cu3O7-delta from CuNQR

C-63,C-65, nuclear quadrupole resonance (NQR) at ambient temperatures has b een performed to probe Ba-site occupation of Pr atoms in Y1-xPTxBa2Cu3O7-de lta (0 less than or equal to x less than or equal to 1.0) Anomalous spectra l peaks were observed. Qualitative comparisons with electric field gradient (FFG) simulations suggest that these extra peaks come from Pr3+ ions on th e Pa site with a concomitant occupation of the anti-chain O(5)-site. The re sults also suggest that this peculiar lattice arrangement has an effect on EFG that is different and distinguishible from that produced by a random ch ain oxygen distribution such as those that occur in underdoped (oxygen-defi cient) YBa2Cu3O7-delta.