Determination of the Ta and Nb ratio in LiNb1−xTaxO3 by total reflection X-ray fluorescence spectrometry

A procedure for evaluation of the mass ratio between Ta and Nb in LiNb1−xTaxO3 single crystals by total reflection X-ray fluorescence spectrometry (TXRF) is described. The developed procedure does not require chemical preparation of the samples and it proves to be fast (30 min for sample preparation and 10 min for analysis), precise (down 1% RSD) and easy to perform. To check the methodology, the lattice parameter of each LiNb1−xTaxO3 sample was determined by powder X-ray diffraction. While the a hexagonal lattice parameter remains constant, a strong and linear dependence of the c hexagonal lattice parameter with Ta content in molar percentage has been observed for the first time.