Calorimetric study of CaCu3Ti4O12, a ceramic with giant permittivity

Andrey A. Levchenko, Loïc Marchin, Yosuke Moriya, Hitoshi Kawaji, Tooru Atake, Sophie Guillemet-Fritsch, Bernard Durand, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We conducted an investigation into the thermodynamic properties of two stoichiometric CaCu3Ti4O12 (CCTO) samples prepared by solid-state reaction and soft chemistry methods to probe the stability of the material relative to simpler oxide constituents (e.g., CaO, CuO, and TiO2) over a wide temperature range. Thermodynamic functions (i.e., heat capacity, formation enthalpies, entropies, and Gibbs free energies) have been measured from near absolute zero to 1100 K using calorimetric methods, including drop solution, low-temperature adiabatic relaxation, and differential scanning calorimetry. In addition, the thermodynamic characteristics of the magnetic-phase transition from the antiferromagnetic to the paramagnetic state are reported. It has been shown that CCTO is very stable relative to constituent oxides and calcium titanate at room temperature and higher, independent of the synthesis route. The enthalpic factor is dominant in the thermodynamics of CCTO, with the entropic factor having almost no effect on the stability of the compound relative to other oxide assemblages. The recommended values for the standard molar enthalpy of formation from constituent oxides and from elements at 298.15 K are -122.1 ± 4.5 and -4155.7 ± 5.2 kJ/mol-1, respectively. The mean of the third law entropy at 298.15 K is 368.4 ±0.1 J/mol-1/K-1. Based on the thermodynamic data reported, the study confirms the possibility of CCTO decomposition in a reducing atmosphere or CO2 under conditions recently observed in experiments.

Original languageEnglish (US)
Pages (from-to)1522-1531
Number of pages10
JournalJournal of Materials Research
Volume23
Issue number6
DOIs
StatePublished - Jun 2008
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint

Dive into the research topics of 'Calorimetric study of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>, a ceramic with giant permittivity'. Together they form a unique fingerprint.

Cite this