Ja. Hodges et al., CU(2) DERIVED MOLECULAR-FIELD ON YB3+ IN TMBA2CU3O6 AND YBBA2CU3O6, Journal of magnetism and magnetic materials, 144, 1995, pp. 1337-1338
Yb-170 Mossbauer measurements in YbBa2Cu3O6 and on Yb3+ ions substitut
ed into TmBa2Cu3O6 show that the ordered Cu(2) sublattice produces a m
olecular field at the rare earth site. The Yb3+ ion is not at a centre
of magnetic inversion symmetry relative to the Cu(2) moments.