Thermal properties of the Nd1−Ca BaCo2O5.5 compositions (0 ≤ x ≤ 0.2)

Gutowska, M.; Wieckowski, J.; Szewczyk, A.; Koleśnik, S.; Dąbrowski, B.; Kowalczyk, M.; Pietosa, J.; Nedelko, N.; Minikayev, R.

doi:10.1016/j.jallcom.2016.01.257

Cited by 5 publications

(1 citation statement)

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“…Fortunately, this can also be done with thermodynamic modeling, but doing so requires knowledge of low-temperature heat capacities (and absolute entropies) of RBaCo 2 O 6−δ . These issues, in particular in view of the anomalies observed for the C p ( T ) dependences of RBaCo 2 O 6−δ at temperatures close to absolute zero, , call for a separate discussion and will be addressed in our future studies.…”

Section: Discussionmentioning

confidence: 97%

Redox Thermochemistry, Thermodynamics, and Solar Energy Conversion and Storage Capability of Some Double Perovskite Cobaltites

et al. 2021

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The oxygen nonstoichiometry, δ, and oxidation enthalpy, ΔH ox , of double perovskites RBaCo 2 O 6−δ (R = Sm or Eu) were simultaneously measured depending on the temperature and oxygen partial pressure, p O 2 . Theoretical equations for ΔH ox (T, δ) and p O 2 (T, δ) were derived from the defect structure model based on the oxygen exchange and cobalt disproportionation reactions. These equations were fitted independently to each of the experimental ΔH ox (T, δ) and p O 2 (T, δ) data sets. The resulting enthalpies of defect reactions were found to be almost the same irrespective of the calculation method. In other words, the models, describing satisfactorily the data, can be used to calculate both compositional dependences and redox thermodynamics of RBaCo 2 O 6−δ (R = Sm or Eu). In addition, from the previously published data and the data presented here, trends were determined in the defect reaction thermodynamics of RBaCo 2 O 6−δ (R = La, Pr, Nd, Sm, Eu, Gd, or Y). Drop calorimetric measurements were performed in air to obtain enthalpy increments for RBaCo 2 O 6−δ (R = Sm or Eu) with variable oxygen content because the samples lost oxygen upon being heated in the calorimetric cell. As-obtained data were used to calculate the functional dependences of enthalpy increments of EuBaCo 2 O 5.56 and SmBaCo 2 O 5.6 with a constant oxygen content. In addition, as an example of practical application-oriented calculations for solar energy conversion and oxygen storage, the performances at equilibrium of RBaCo 2 O 6−δ (R = Pr, Sm, Eu, or Gd) were evaluated and compared to those of SrFeO 3−δ as a reference material.

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Section: Discussionmentioning

confidence: 97%