GeTe-Bi2Te3-Te System

Alloys of the GeTe-Bi2Te3-Te system synthesized by a special technique in a state as close to equilibrium as possible, have been characterized by differential thermal analysis (DTA), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). An equilibrium solid phase diagram, the liquidus surface projection, selected polythermal sections, and the 300-K isothermal section of the phase diagram have been constructed. The primary crystallization fields of phases, types and coordinates of invariant and monovariant equilibria have been determined. Monovariant equilibria on curves originating from the peritectic points and eutectic point of the GeTe-Bi2Te3 boundary system undergo transformations at certain transition points. A cascade of invariant transition reactions has been identified near the tellurium corner of the concentration triangle, characterizing the joint crystallization of two-phase mixtures of telluride phases and elemental tellurium.