Time-differential perturbed-angular-correlation studies on 117In and 111Cd in Li0.995Cd0.005NbO3

The nuclear-electric-quadrupole interactions at 117In and 111Cd nuclei arising from 117Cd and 111mCd, respectively, chemically introduced in Li0.995Cd0.005NbO3 polycrystals were studied using the time-differential perturbed angular correlation of γ rays. The |Vzzlattice| values derived for 117In and 111Cd coincided with each other, i.e., 3.4(1)x1020V/m2 and 3.4(5)x1020V/m2, respectively, meaning that the In and Cd ions are in the same lattice environment in the forms of In3+ and Cd2+. Although these probes are considered to occupy the Li sites, the above values of Vzzlattice are substantially different from the previously reported value for 7Li, 0.7x1020V/m2, which is ascribable to the structural relaxation around the probe atoms. The temperature dependence of ωQ of 117In indicates that the In ion vibrates anisotropically about its equilibrium position at high temperatures, as has been argued for the Li ion in LiNbO3. copyright 1997 The American Physical Society