Phase Competition in the Palmer-Chalker <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi><mml:mi>Y</mml:mi></mml:math> Pyrochlore <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>Er</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>Pt</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
Bibliographic record
Abstract
We report neutron scattering measurements on ${\mathrm{Er}}_{2}{\mathrm{Pt}}_{2}{\mathrm{O}}_{7}$, a new addition to the $XY$ family of frustrated pyrochlore magnets. Symmetry analysis of our elastic scattering data shows that ${\mathrm{Er}}_{2}{\mathrm{Pt}}_{2}{\mathrm{O}}_{7}$ orders into the $k=0$, ${\mathrm{\ensuremath{\Gamma}}}_{7}$ magnetic structure (the Palmer-Chalker state), at ${T}_{N}=0.38\text{ }\text{ }\mathrm{K}$. This contrasts with its sister $XY$ pyrochlore antiferromagnets ${\mathrm{Er}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ and ${\mathrm{Er}}_{2}{\mathrm{Ge}}_{2}{\mathrm{O}}_{7}$, both of which order into ${\mathrm{\ensuremath{\Gamma}}}_{5}$ magnetic structures at much higher temperatures, ${T}_{N}=1.2$ and 1.4 K, respectively. In this temperature range, the magnetic heat capacity of ${\mathrm{Er}}_{2}{\mathrm{Pt}}_{2}{\mathrm{O}}_{7}$ contains a broad anomaly centered at ${T}^{*}=1.5\text{ }\text{ }\mathrm{K}$. Our inelastic neutron scattering measurements reveal that this broad heat capacity anomaly sets the temperature scale for strong short-range spin fluctuations. Below ${T}_{N}=0.38\text{ }\text{ }\mathrm{K}$, ${\mathrm{Er}}_{2}{\mathrm{Pt}}_{2}{\mathrm{O}}_{7}$ displays a gapped spin-wave spectrum with an intense, flat band of excitations at lower energy and a weak, diffusive band of excitations at higher energy. The flat band is well described by classical spin-wave calculations, but these calculations also predict sharp dispersive branches at higher energy, a striking discrepancy with the experimental data. This, in concert with the strong suppression of ${T}_{N}$, is attributable to enhanced quantum fluctuations due to phase competition between the ${\mathrm{\ensuremath{\Gamma}}}_{7}$ and ${\mathrm{\ensuremath{\Gamma}}}_{5}$ states that border each other within a classically predicted phase diagram.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.005 | 0.004 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.136 | 0.047 |
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".