Specific heat study and Landau analysis of the phase transition in PbTiO<sub>3</sub>single crystals
Bibliographic record
Abstract
The specific heat of pure lead titanate (PbTiO 3 ) crystals grown by the float-zone method is reported at temperatures of 325–1250 K. The excess specific heat associated with the ferroelectric phase transition was analysed using a 2–4–6 Landau potential to self-consistently determine the Curie–Weiss temperature, the transition points, the total transition enthalpy, as well as the latent heat and entropy discontinuity at the first-order phase change. The temperature ranges over which various excess thermodynamic quantities obeyed the mean-field predictions of the Landau theory were investigated. The coefficients of the Landau potential were also determined, and the results compared to corresponding measurements made on pure polycrystalline lead titanate specimens. The implications of the results with respect to prior discrepancies reported for the first-order character of the phase transition in lead titanate crystals are discussed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".