Damped soft phonons and diffuse scattering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>40</mml:mn><mml:mo>%</mml:mo><mml:mi>Pb</mml:mi><mml:mo>(</mml:mo><mml:msub><mml:mi>Mg</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>∕</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>Nb</mml:mi><mml:mrow><mml:mn>2</mml:mn><mml:mo>∕</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mo>)</mml:mo><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mtext>−</mml:mtext><mml:mn>60</mml:mn><mml:mo>%</mml:mo><mml:msub><mml:mi>PbTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>
Bibliographic record
Abstract
Using neutron elastic and inelastic scattering and high-energy x-ray diffraction, we present a comparison of $40%\phantom{\rule{0.3em}{0ex}}\mathrm{Pb}({\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}\text{\ensuremath{-}}60%\phantom{\rule{0.3em}{0ex}}{\mathrm{PbTiO}}_{3}$ (PMN-60PT) with pure $\mathrm{Pb}({\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}$ (PMN) and ${\mathrm{PbTiO}}_{3}$ (PT). We measure the structural properties of PMN-60PT to be identical to pure PT, however, the lattice dynamics are exactly that previously found in relaxors PMN and $\mathrm{Pb}({\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}$ (PZN). PMN-60PT displays a well-defined macroscopic structural transition from a cubic to tetragonal unit cell at $550\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The diffuse scattering is shown to be weak indicating that the structural distortion is long-range in PMN-60PT and short-range polar correlations (polar nanoregions) are not present. Even though polar nanoregions are absent, the soft optic mode is short-lived for wave vectors near the zone center. Therefore PMN-60PT displays the same waterfall effect as prototypical relaxors PMN and PZN. We conclude that it is random fields resulting from the intrinsic chemical disorder which is the reason for the broad transverse optic mode observed in PMN and PMN-60PT near the zone center and not due to the formation of short-ranged polar correlations. Through our comparison of PMN, PMN-60PT, and pure PT, we interpret the dynamic and static properties of the $\mathrm{PMN}\text{\ensuremath{-}}x\mathrm{PT}$ system in terms of a random field model in which the cubic anisotropy term dominates with increasing doping of ${\mathrm{PbTiO}}_{3}$.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.145 | 0.028 |
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".