Akademik Məlumat İdarəetmə Sistemi
Kondensirovannye Sredy Mezhfaznye Granitsy, vol.22, no.4, pp.460-465, 2020 (Scopus)
Compounds of the Tl4LnTe3 (Ln-Nd, Sm, Tb, Er, Tm) composition were synthesized by the direct interaction of stoichiometric amounts of thallium telluride Tl2Te elementary rare earth elements (REE) and tellurium in evacuated (10-2 Pa) quartz ampoules. The samples obtained were identified by differential thermal and X-ray phase analyses. Based on the data from the heating thermograms, it was shown that these compounds melt with decomposition by peritectic reactions. Analysis of powder diffraction patterns showed that they were completely indexed in a tetragonal lattice of the Tl5Te3 type (space group I4/mcm). Using the Le Bail refinement, the crystal lattice parameters of the synthesized compounds were calculated. It was found that when the thallium atoms located in the centres of the octahedra were substituted by REE atoms, there occurred a sharp decrease in the a parameter and an increase in the c parameter. This was due to the fact that the substitution of thallium atoms with REE cations led to the strengthening of chemical bonds with tellurium atoms. This was accompanied by some distortion of octahedra and an increase in the c parameter. A correlation between the parameters of the crystal lattices and the atomic number of the lanthanide was revealed: during the transition from neodymium to thulium, there was an almost linear decrease in both parameters of the crystal lattice, which was apparently associated with lanthanide contraction. The obtained new compounds complement the extensive class of ternary compounds - structural analogues of Tl5Te3 and are of interest as potential thermoelectric and magnetic materials.