Oxygen isotope effect in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>0.8</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>0.2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MnO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>and its dependence on oxygen stoichiometry
Bibliographic record
Abstract
The oxygen isotope effect of the ferromagnetic transition temperature was investigated in various samples of the manganite ${\mathrm{La}}_{0.8}{\mathrm{Ca}}_{0.2}{\mathrm{MnO}}_{3+\ensuremath{\delta}},$ as a function of sintering conditions. Sintering at 1200 \ifmmode^\circ\else\textdegree\fi{}C and above leads to oxygen-stoichiometric comparison samples with an isotope exponent of ${\ensuremath{\alpha}}_{\mathrm{O}}=0.41\ifmmode\pm\else\textpm\fi{}0.02,$ and transition temperatures ${T}_{C}(16)=189\ifmmode\pm\else\textpm\fi{}2 \mathrm{K}$ and ${T}_{C}(18)=180\ifmmode\pm\else\textpm\fi{}2 \mathrm{K}.$ Samples sintered at 1000 \ifmmode^\circ\else\textdegree\fi{}C, and below, always have oxygen excess. The oxygen excess leads to vacancies at the $A(\mathrm{L}\mathrm{a},\mathrm{C}\mathrm{a})$ and $B(\mathrm{Mn})$ sites, leading to a decrease in unit cell volume. The unit cell volume is identical for both isotopes, and this implies equal oxygen content for the isotopic comparison samples. The isotope exponent ${\ensuremath{\alpha}}_{\mathrm{O}}$ for oxygen excess samples is much larger than 0.4. Its value, as well as the transition temperatures ${T}_{C},$ depends on the ${\mathrm{Mn}}^{4+}$ concentration, as well as the defect structure induced by A and B sites vacancies.
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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 | 0.009 | 0.007 |
| Meta-epidemiology (narrow) | 0.004 | 0.009 |
| Meta-epidemiology (broad) | 0.002 | 0.008 |
| Bibliometrics | 0.003 | 0.006 |
| Science and technology studies | 0.006 | 0.007 |
| Scholarly communication | 0.007 | 0.007 |
| Open science | 0.010 | 0.009 |
| Research integrity | 0.010 | 0.007 |
| Insufficient payload (model declined to judge) | 0.986 | 0.014 |
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; both teacher heads agree on what is shown here.
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".