Experimental evidence of symmetry breaking in the multiferroic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ba</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>NbFe</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Si</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>14</mml:mn></mml:msub></mml:mrow></mml:math> using sound velocity measurements
Bibliographic record
Abstract
Using high-resolution sound velocity measurements, we determined the temperature dependence of the principal elastic constants of the multiferroic compound ${\mathrm{Ba}}_{3}{\mathrm{NbFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}$ at different magnetic fields. All four elastic constants revealed an anomaly at ${T}_{N}=27.1(1)$ K, which coincides very well with the emergence of the magnetic chiral state. More importantly, we carried out velocity measurements as a function of a field rotating in the basal trigonal plane at different fields and temperatures. In particular, in the magnetically ordered state, we observed an angular hysteresis of $\mathrm{\ensuremath{\Delta}}{C}_{11}/{C}_{11}$, which might be associated with the field-induced ferroelectric polarization suddenly switching from the ${b}^{*}$ axis to the $a$ direction, due to the magnetoelectric effect previously observed in ${\mathrm{Ba}}_{3}{\mathrm{NbFe}}_{3}{\mathrm{Si}}_{2}{\mathrm{O}}_{14}$. The data analysis also leads to an estimate for the lattice distortion $({e}_{1}\ensuremath{-}{e}_{2}\ensuremath{\le}{10}^{\ensuremath{-}5})$ accounting for a symmetry reduction in the magnetic chiral state possibly associated with the induced polarization along the $a$ axis in zero field.
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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 | 0.011 | 0.010 |
| Meta-epidemiology (narrow) | 0.004 | 0.006 |
| Meta-epidemiology (broad) | 0.002 | 0.007 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.006 | 0.007 |
| Scholarly communication | 0.006 | 0.006 |
| Open science | 0.011 | 0.008 |
| Research integrity | 0.005 | 0.006 |
| Insufficient payload (model declined to judge) | 0.598 | 0.007 |
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".