Structure, oxygen non-stoichiometry and thermal properties of (Bi0.4Sr0.6)Sr2CoO5–δ

Abstract

We synthesized and characterized (Bi0.4Sr0.6)Sr2CoO5−δ using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS). In the next step the heat capacity and enthalpy increments of (Bi0.4Sr0.6)Sr2CoO5−δ were measured by physical property measurement system (PPMS), differential scanning calorimetry (DSC) and drop calorimetry. Oxygen non-stoichiometry was determined using thermogravimetric measurement (TG) and reduction in hydrogen atmosphere. Above room temperature the temperature dependence of the molar heat capacity in the form Cpm=(201.0+0.09261×T−2184097×T−2)JK−1mol−1 was derived by the least squares method from the experimental data. The heat capacity was also analyzed in terms of a combined Debye–Einstein model. The molar entropy Sm° (298.15)=219.65Jmol−1K−1 was evaluated from the low temperature heat capacity data.