Growth and the Actual Compositions of Cation‐Deficient Sodium‐Gadolinium Molybdate Single Crystals

Abstract

The concentration series of sodium‐gadolinium molybdate (NGM) crystals have been grown by Czochralski technique from stoichiometric Na0,5Gd0,5MoO4 melt, and from seven different nonstoichiometric melts in various atmospheres. The actual cation compositions of the crystals are measured by microprobe analysis. The location of the congruently melting composition is found for this compound, and the homogeneity field is evaluated. The unit cell parameters of the crystals have been calculated from X‐ray diffraction (XRD) analysis results. Hydrostatic densities of the crystals are measured. Based on these results, the actual molar weights of the samples are calculated that allows more precise determination of the crystals compositions. The studied crystals are shown to contain substantial sodium deficiency and excess of gadolinium compared to stoichiometry. The amount of cation vacancies occurs in both sublattices along with increase of Gd2O3/Na2O molar ratio in the crystals.

CaMoO-=SUB=-4-=/SUB=--NaGd(MoO-=SUB=-4-=/SUB=-)-=SUB=-2-=/SUB=- Solid Solutions: simulation of properties and local structure by the method of interatomic potentials

“…And only for the modulus of elasticity maximum differences are 3.4% for the 7 × 2 × 2 supercell and 1.6% for the 6 × 3 × 2 supercell. Also, Table 2 presents the variation range of experimental values of the studied properties according to the data from [19][20][21][22] for the NGM crystals grown from stoichiometric composition. The differences connected with the use of different approximations are comparable with the scattering of experimental data or less than it.…”