Thermodynamic evidence for structural phase transitions in the liquid state of the binary chalcogenide systems

Abstract

Thermodynamic functions of the binary chalcogenide systems, S-Se, S-Te and Se-Te, have been analyzed to provide evidence for structural phase transitions in the liquid state of tellurium-rich alloys. A cusp-like minimum in the enthalpy of mixing as a function of concentration observed for the last two systems is in consequence of the steep increase in the enthalpies of tellurium-rich alloys in the narrow temperature range. Apparent complications in the thermodynamic functions are indicative of structural phase transitions rather than some local order in the liquid state. The inhomogeneous structure model of Tsuchiya and Seymour (1982, 1985) can consistently explain these characteristic features of thermodynamic functions together with other thermodynamic properties.