Yttrium niobates

Yttrium tantalate and yttrium niobate-tantalate have good X-ray absorption and are used in X-ray intensifying screens because of their high conversion factor (Section 5.5.4.2.). Substitution of tantalum by small quantities of niobium considerably increases the blue fluorescence when excited by X rays. 

A study of europium niobates showed that the crystallization processes and kinetics of growth were similar to those reported for the yttrium niobates. The emission spectra of Cs2NaEuCl and Cs2Na(EUjcYi, )Cl6 confirmed that the europium atom in each compound was situated at a site of perfect octahedral symmetry and was surrounded by six chloride ions in a face-centred cubic structure. ... 

In 1877, Mallet discovered an yttrium niobate mineral called sipylite in Virginia (USA). Analyzing it he found that it contained niobium and cerium and yttrium group elements (Mallet 1877). In 1878, Delafontaine identified Marignac s ytterbium in this mineral too (Delafontaine 1878d). 

Compared with the high symmetry of site, the asymmetrical fields have a drastic influence on the spectroscopic properties of Bi ". The lowest excitation level shifts toward higher energy, whereas the Stokes shift increases. The Se site has better resistance to thermal impact than the C2 site at higher temperature [57]. A similar conclusion was reported in Bi -doped yttrium or gadolinium niobates [58]. 

S. Shastry, G. Srinivasan, M. 1. Bichurin, V. M. Petrov, A. S. Tatarenko, Microwave magnetoelectric effects in single crystal bilayers of yttrium iron garnet and lead magnesium niobate-lead titanate, PAys. Rev. B, 70, 064416, (2004). 

Conversely, oxides such as GGG, sapphire, the niobates and tantalates are routinely controlled by the weighing method. Even neodymium-doped yttrium... 

Strontium cobalt ferrites are good mixed conductors but are more suitable to be used as cathodes due to their p-type conduction. Pervoskite gaUates/niobates/barium cerate and chromium-doped lanthanum-strontium ferrite have also been studied as the anode material. Although the gaUates and niobates exhibit low conductivity, they exhibit good compatibihty with the LSGM electrolytes. The conductivity of yttrium-doped barium cerates increases by increasing yttrium content. For barium cerates, the increase in electronic conduction due to the reduction of cerium at low... 

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