Abstrakt
The structure and oxygen non-stoichiometry of misfit layered cobaltite Ei(1.85)Sr(2)Co(1.85)O(7.7-delta) was determined by Rietveld analysis and by thermogravimetric measurements. The heat capacity and enthalpy increments of pseudo-ternary oxide Ei(1.85)Sr(2)Co(1.85)O(7.7-delta) was measured by the relaxation time method (PPMS) from 2 K to 256 K, by differential scanning calorimetry (DSC) from 258 K to 355 K and by the drop calorimetry from 573 K to 1153 K.
Above room temperature the temperature dependence of the molar heat capacity in the form C-pm = (305.8 + 0.07325. T - 4702536 T-2)J K-1 mol(-1) was derived by the least-squares method from the experimental data.
The heat capacity was analyzed in terms of a combined Debye-Einstein model. The molar entropy S-m(o)(298.15) = 317.7J mol(-1) K-1 was evaluated from the low temperature heat capacity measurements. (C) 2014 Elsevier B.V.
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