Impurity Cationic-Site Population and Electric-Field Gradient Dependence on Ionic Size in Bixbyite Sesquioxides Implanted with 181Hf -->181Ta

M. RENTERÍA; A.G. BIBILONI; F.G. REQUEJO; A.F. PASQUEVICH; J. SHITU; K. FREITAG

MODERN PHYSICS LETTERS B

WORLD SCIENTIFIC PUBL CO PTE LTD

Lugar: London, UK; Año: 1998 vol. 12 p. 819 - 827

0217-9849

The Perturbed-Angular-Correlation technique was used to study the impurity cationic-site population and electric-field gradients in scandium and samarium sesquioxides implanted with 181Hf → 181Ta. We found a departure of the tantalum (hafnium) relative occupancy of the crystallographic sites C and D in the bixbyite structure from the natural abundance of the sites, in the case of scandium sesquioxide, that could be explained in terms of the small lattice parameter of this sesquioxide. A similar behavior occurs in the case of indium sesquioxide. In the rest of the bixbyites measured with 181Ta, fD/fC remains nearly constant and close to the crystallographic abundance, which is only reached in the case of Sm2O3, the sesquioxide with the largest lattice parameter. Additionally, we confirm a jump in the values of νQ(Ta) for sites C and D that takes place for a ≤ 1:012 nm, that is for lattice parameters smaller than that of ytterbium sesquioxide.