Crystal structures and phase transition in (Sr<sub>0.8</sub>Ce<sub>0.2</sub>)(Mn<sub>1−<i>y</i></sub>Co<sub><i>y</i></sub>)O<sub>3</sub>(<i>y</i>= 0 and 0.2): the influence of Jahn–Teller distortion
Bibliographic record
Abstract
We have studied the crystal structures of (Sr(0.8)Ce(0.2))(Mn(1-y)Co(y))O(3) (y = 0 and 0.2) using neutron diffraction. Both (Sr(0.8)Ce(0.2))MnO(3) and (Sr(0.8)Ce(0.2))(Mn(0.8)Co(0.2))O(3) have a tetragonal structure in space group I4/mcm at room temperature, and the octahedral tilt angle around the c-axis is nearly the same. The only significant difference is the shape of the Mn(Co)O(6) octahedron: it is elongated in (Sr(0.8)Ce(0.2))MnO(3) due to the cooperative Jahn-Teller (JT) effect, but essentially regular in (Sr(0.8)Ce(0.2))(Mn(0.8)Co(0.2))O(3) due to the absence of JT-active Mn(3+) ions. With increasing temperature, both compounds undergo a continuous phase transition at around 400 °C to a cubic structure in [Formula: see text], with no indication of a distinct transition in (Sr(0.8)Ce(0.2))MnO(3) from the removal of the static JT distortion. In addition, the temperature dependence of the octahedral tilt angle is very similar in the two samples, implying that the JT distortion has minimal effect on the octahedral tilting and the phase transition to cubic. X-ray absorption near-edge structure (XANES) analysis indicates that the Ce oxidation state is predominantly 4+ in both samples. The electrical conductivity is higher in (Sr(0.8)Ce(0.2))MnO(3) than in (Sr(0.8)Ce(0.2))(Mn(0.8)Co(0.2))O(3) in the temperature range studied (100-900 °C).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.002 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".