Non-ionic contributions to the electric-field gradient at 111 Cd/ 181 Ta impurities in bixbyites

M. RENTERÍA; K. FREITAG; L.A. ERRICO

HYPERFINE INTERACTIONS

Kluwer Pub

Lugar: Dordrecht; Año: 1999 vol. 120 p. 449 - 455

0304-3843

Vol. 120/121The electric-field-gradient (EFG) tensor at both cation sites of the bixbyite structure in 181Hf-implanted Lu- and Sm-sesquioxides was determined by the PAC technique. The cumulated EFG data at Ta-impurity sites in binary oxides enable us to discuss the "universal" character of the empirical correlation between local and ionic contributions to the EFG in these systems. An EFG factorization in terms of the electronic characteristics of the probe and the geometry of the cation coordination is proposed, which explains the experimental EFG results at Ta/Cd impurity sites in bixbyites and agrees with a simplified decomposition of the EFG valence contribution coming from ab-initio calculations.