PAC-studies of Sn-doped In₂O₃: electronic defect relaxation following the ¹¹¹In(EC)¹¹¹Cd-decay

Abstract

Perturbed γ-angular correlation measurements as function of the measuring temperature and the Sn-content have been performed in Sn-doped cubic In₂O₃ using ¹¹¹In(EC)¹¹¹Cd and ^111mCd probes. By comparing the spectra of both isotopes, electronic relaxation phenomena, socalled decay after-effects, following the electron capture radioactive decay of ¹¹¹In, were established. A time independent loss of the static quadrupole interaction amplitudes was found to be characteristic for the electronic relaxation, and its temperature and do** dependence were measured. The high statistical accuracy of the PAC-data allowed a separation between structural and dynamic effects and the observation of each lattice site’s behaviour. Relaxation rates were extracted from numerical simulations based on Blume’s theory and related to the predominant electron transport mechanisms in In₂O₃, especially, with rising Sn-content, to the transition to metallic conduction.