Heat capacity and thermodynamic functions of new cobalt manganites NdM2I CoMnO5 (MI = Li, Na, and K) in the range of 298.15–673 K

Abstract

Temperature dependences of the heat capacity of cobalt manganites NdM₂^I CoMnO₅ (M^I = Li, Na, and K) are studied by means of dynamic calorimetry in the range of 298.15−673 K. It is found that λ-shaped effects are observed on the C_p^° ~ f (T) curve of cobalt manganites, due probably to second order phase transitions. Based on the experimental data, equations for the temperature dependences of the heat capacity of cobalt manganite are derived with allowance for the temperatures of phase transitions. The values of thermodynamic functions Н°(T)–Н°(298.15), S°(T), and Ф^хх(T) are calculated.