Examining Order–Disorder Structural Transition of Gd<sub>2</sub>Zr<sub>2–<i>x</i></sub>Ce<sub><i>x</i></sub>O<sub>7</sub> Using Synchrotron Techniques
Bibliographic record
Abstract
Depending on the radius ratio of A and B site cations, A 2 B 2 O 7 -type oxides can adopt different crystal structures, including the pyrochlore-, defect fluorite-, or bixbyite-type structures. Gd 2 Zr 2 O 7 with a r Gd 3+ / r Zr 4+ ratio of 1.46 is an example that exhibits a polymorphic transition between the pyrochlore- and defect fluorite-type structures. To delve deeper into these polymorphic transitions, Ce was introduced as a substitute in the B-site of Gd 2 Zr 2 O 7 . Gd 2 Zr 2– x Ce x O 7 (0 ≤ x ≤ 2) was synthesized using a coprecipitation method and annealed at 1400 °C. Previous investigations yielded disparate results regarding the structures adopted due to the challenge of detecting the low-intensity superstructural peaks associated with the pyrochlore and bixbyite structures using conventional lab-based X-ray diffraction (XRD) instruments. Utilizing synchrotron XRD with a high signal/noise ratio resolves these contradictions and aids in the structure analysis for Gd 2 Zr 2– x Ce x O 7 . Based on synchrotron XRD data, a combination of defect fluorite and pyrochlore phases was observed for x = 0–0.25, the defect fluorite structure was adopted when x = 0.5–1.75, and the bixbyite structure was observed when x = 2. Ce L 3 and Zr K-edge X-ray absorption near edge spectroscopy (XANES) spectra revealed that both cations were present in 4+ oxidation states.
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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".