2004 Volume 45 Issue 7 Pages 1998-2002
The nuclear-electric-quadrupole interactions at 111Cd and 117In nuclei arising from 111mCd and 117Cd, respectively, chemically introduced in pyrochlore ferroelectric Cd2Nb2O7 (TC = 196 K) were studied using the perturbed-angular-correlation technique. At temperatures above TC, there is one type of Cd sites. However, at liquid nitrogen temperature, below TC, there are two types of Cd sites. The ratio of the electric quadrupole frequency of 117In to that of 111Cd is anomalously deviated from a value expected from the purely ionic In and Cd ions in the same lattice environment.