Low-temperature heat capacity VO2±δ and solid solutions V1-XFeXO2

Abstract

The article reports the study results of the heat capacity of vanadium dioxide compounds (VO2) (within the homogeneity range) and stoichiometric solid solutions V1-xFexO2 at temperature range from 5 κ to 100 κ. Separation of various constituents of heat capacity with its additivity assumption has been conducted: crystal lattice heat capacity and defects heat capacity. It is shown that a considerable contribution to the heat capacity is produced by the crystal lattice defects (till ~ 25 κ) at low temperatures, and at higher temperatures the heat capacity is determined mainly with the crystal lattice. Using the Debye function table for the heat capacity for all compounds, the characteristic Debye temperatures θD were determined.