The Pr-141 Mossbauer isomer shift and hyperfine field spectrum of PrBa
2CU3O7-y were measured at 25 and 4.2 K, respectively. The isomer shift
corresponds to an intermediate valency of 3.4(1) and the hyperfine fi
eld spectrum at 4.2 K seems to indicate a hyperfine field of 29(3) T.