PHASE RELATIONS AND CHARACTERIZATION OF SOLID SOLUTIONS IN THE SnBi<sub>2</sub>Te<sub>4</sub>-PbBi<sub>2</sub>Te<sub>4</sub> AND SnBi<sub>4</sub>Te<sub>7</sub>-PbBi<sub>4</sub>Te<sub>7</sub> SYSTEMS
Phase equilibria in SnBi<sub>2</sub>Te<sub>4</sub>-PbBi<sub>2</sub>Te<sub>4</sub> and SnBi<sub>4</sub>Te<sub>7</sub>-PbBi<sub>4</sub>Te<sub>7</sub> systems were studied using differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. It has been shown that both systems are characterized by the formation of a continuous series of solid solutions with a tetradymite-like layered structure. The lattice parameters of solid solutions are linear functions of composition