If we want to know the ferroelectric, magnetic and structural transitions from DSC, what is our approach and how are these properties related to thermodynamics and DSC parameters?
Does anyone have any recommendations for papers in this area?
These are second order transitions with no enthalpy drop, but with a possibly large change of heat capacity. This is reflected in a DSC trace by a knee of the base line.
In a suitably calibrated instrument the shift of the base line is a direct measure of the heat capacity change.
The answer to this question is that we should analyse DSC carefully, using a very precious tool: our brain!
Two key points:
- are these transitions correlated to thermal effects?
- Select the optimum heating rate. Too many people use low heating rates, showing they have not understood DSC.
https://www.researchgate.net/publication/227055095_Solid-hydroxide_protonic_conductors_Superionic_conductivity_phase_transitions_isotopic_effect_and_self-organized_microheterogeneity
Article Solid-Hydroxide Protonic Conductors: Superionic Conductivity...
DSC is not a very sensitive method for changes in these properties as a function of temperature. They show up as changes in the heat capacity of the system. A better method is to run a TGA in an external magnetic field. Changes in properties show up as apparent loss or gain in weight.
I my opinion the DSC method is not got four your analysis. I propose dilatometry investigations for phase transformation, or XRD in sintu tests
Calorimetric measurements in standard devices (i.e., DSC) furnishes "partial" results clearly influenced by the inner structure of the device and the temperature and flow rates. The heat transfer was not strictly modeled by one heat capacity and a thermal resistance. One is the point of view of advertising: all is perfect and excellent, other was the Metrologic point of view. Carefully analysis requires higher brain consumption. I suggest one of my papers (and references therein) for models work:
Identification of micro-scale calorimetric devices - IV. Descriptive models in 3-D
Author(s): Auguet, C; Lerchner, J; Marinelli, P; et al. Source: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY Volume: 71 Issue: 3 Pages: 951-966
Each analysis and quantitative measurements cannot be solved by a "cut and paste" answer. Always requires extensive participation of the authors. You need to read the classical book of Hemminger and Hohne about DSC and, later built a model of your device (i.e., by several heat capacities), realize calibrations and good luck!!. Remember: always was required a 10 % of inspiration adding other 90 % of transpiration.
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