ELECTRIC-FIELD GRADIENTS AT CD-111 IN M2CU2O5 CUPRATES (M=SC, Y, IN, LU, YB, HO, TB)

Perturbed angular correlation spectroscopy has been used to study the hyperfine interaction at (In(EC)Cd)-In-111-Cd-111 in several cuprates M2Cu2O5 (M = Sc, Y, In, Lu, Yb, Ho, Tb) with Ho2Cu2O5 structure. The radioactive In-111 probes were either ion implanted or chemically introduced into polycrystalline powder samples. Two electric field gradients, populated with equal fractions by the (In(EC)Cd)-In-111-Cd-111 probes, have been attributed to the two octahedral M sites. A smooth variation of the hyperfine parameters with the ion radius of the M elements was observed and traced back to the variation of the position of the oxygen ion connecting the two M sites.