Hyperfine interactions in 111Cd-doped lutetium sesquioxide

We report here first Perturbed Angular Correlation (PAC) results of the electric field gradient (EFG) characterisation at ¹¹¹Cd impurities located at both non-equivalent cation sites of the bixbyite structure of Lutetium sesquioxide, between room temperature (RT) and 1273 K. The comparison with results coming from a systematic ¹¹¹Cd PAC study in bixbyites and with point-charge model (PCM) predictions shows the presence of a trapped defect at RT in the neighbourhood of the asymmetric cation site, which is completely removed at T > 623 K. The anomalous EFG temperature dependence in Lu₂O₃ can be described in the frame of a “two-state” model with fluctuating interactions, which enables the experimental determination of the acceptor energy level introduced by the Cd impurity in the band-gap of the semiconductor and the estimation of the oxygen vacancy density in the sample. This revised version was published online in August 2006 with corrections to the Cover Date.