Megahertz dynamics in skyrmion systems probed with muon-spin relaxation
Bibliographic record
Abstract
We present longitudinal-field muon-spin relaxation (LF $\ensuremath{\mu}\mathrm{SR}$) measurements on two systems that stabilize a skyrmion lattice (SkL): ${\mathrm{Cu}}_{2}{\mathrm{OSeO}}_{3}$, and ${\mathrm{Co}}_{x}{\mathrm{Zn}}_{y}{\mathrm{Mn}}_{20\ensuremath{-}x\ensuremath{-}y}$ for $(x,y)=(10,10)$, (8, 9), and (8, 8). We find that the SkL phase of ${\mathrm{Cu}}_{2}{\mathrm{OSeO}}_{3}$ exhibits emergent dynamic behavior at megahertz frequencies, likely due to collective excitations, allowing the SkL to be identified from the $\ensuremath{\mu}\mathrm{SR}$ response. From measurements following different cooling protocols and calculations of the muon stopping site, we suggest that the metastable SkL is not the majority phase throughout the bulk of this material at the fields and temperatures where it is often observed. The dynamics of bulk ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{9}{\mathrm{Mn}}_{3}$ are well described by $\ensuremath{\simeq}2$ GHz excitations that reduce in frequency near the critical temperature, while in ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4}$ we observe similar behavior over a wide range of temperatures, implying that dynamics of this kind persist beyond the SkL phase.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".