Cuprates of composition (Gd1-xRx)2CuO4, R = Pr, Nd, Sm, Eu, have been
studied by Gd-155 Mossbauer spectroscopy and by complementary experime
ntal techniques. The results provide new evidence for the important in
fluence of exchange interactions between Cu and rare-earth 4f-moments
on rare-earth magnetism in these compounds.