Abstract
Thermodynamic studies on CaLaFe11O19(s) were carried out using Knudsen effusion mass spectrometry and calorimetry, viz. differential scanning calorimetry and high temperature oxide melt solution calorimetry. Standard molar Gibbs free energy of formation (ΔfG 0m), enthalpy of formation and heat capacity (C 0p, m) of the compound were calculated as a function of temperature for the first time. C0p, m(CaLaFe 11O19) was determined and used for second law analysis, from which enthalpy and entropy of formation of the compound were calculated and the respective values are: ΔfH0m(298.15 K)/kJ mol-1=-6057(±8) and S0m(298.15 K)/J K-1 mol-1=427(±5). ΔfH 0m(298.15 K)/kJ mol-1: -6055(±6) was also calculated using oxide melt solution calorimetry, which is in close agreement with the second law value. A heat capacity anomaly was also observed at T=684 K. A table of thermodynamic data from 298.15 K to 1000 K for CaLaFe11O19(s) was also constructed to represent an optimized set of data.
Original language | English (US) |
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Pages (from-to) | 68-74 |
Number of pages | 7 |
Journal | Journal of Solid State Chemistry |
Volume | 201 |
DOIs | |
State | Published - May 2013 |
Externally published | Yes |
Keywords
- Curie temperature
- Differential scanning calorimetry (DSC)
- Magnetic materials
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry