Impurity energy levels in ABO3 perovskites

R. E. ALONSO; A.P. AYALA; P. DE LA PRESA; A. LÓPEZ GARCÍA

Anales del Anniversary of the Hyperfine Interactions at La Plata

Año: 1995 vol. 1 p. 47 - 49

In the last years, several ABO$_3$ perovskite-type compounds were studied using the PAC technique to determine the quadrupole interaction at an impurityprobe. These studiesallowed the characterisation of these materials from its microscopic properties.Some of these works reported unexpected by symmetry low and wide distributed EFG at B sites \cite{al1, al2,cat1}. The EFG detected was commongly associated with the presence of oxygen vacancies and defects. In this work it is presented for the first time a simple computational modelthat reproduces some of the features observed experimentally. The presenceof a distributed EFG in cubic phases is caused by a randomdistribution of a polarised oxygen vacancy-charge. Moreover, the measureddependence of the mean value of the EFG with composition in \batifo for 0 \(<\) x \(<\) 1 was accounted by simulating the different covalency for the Hf and Ti cations.