MgAl<sub>2</sub>O<sub>4</sub> synthetic spinel: cation and vacancy distribution as a function of temperature, from in situ neutron powder diffraction
Bibliographic record
Abstract
Neutron powder diffraction data collection has been carried out at BENSC (Berlin, D), on synthetic Mg0.94Al2.04O4 spinel, in the temperature range 300-1700 K, to investigate the intracrystalline cation and vacancy order-disorder (OD) reaction, which begins to be detectable at 944 K. The Rietveld method has been used in combination with advanced minimization techniques to determine the occupancy coefficients of magnesium, aluminum, and vacancies on the tetrahedral and octohedral sites. The temperature dependence of the cell parameter, of the T-O and M-O bond lengths, and of the oxygen u-coordinate are discussed in the light of the OD-reactions. The cation site partitioning has been interpreted as a function of temperature using the thermodynamic model of O´Neill and Navrotsky, whose parameters [α=30(2) and β=1(3) kJ/mol]are compared with earlier determinations from literature.
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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 | 0.000 | 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".