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Bibliographic record
Abstract
We have performed muon spin relaxation $(\ensuremath{\mu}\mathrm{SR})$ studies on single crystals of $\mathrm{Sr}{\mathrm{Cu}}_{2}{(\mathrm{B}{\mathrm{O}}_{3})}_{2}$, a quasi-two-dimensional spin system with a spin-singlet ground state. We find evidence for two different muon sites which we associate with muons located adjacent to the two inequivalent O sites. One site, presumably located in the Cu-O-Cu superexchange path, exhibits a large increase in the frequency shift with decreasing temperature which is unaffected by the onset of the singlet ground state, indicating that the muon has perturbed the Cu-Cu interaction and created two quasifree spins. We have also performed $\ensuremath{\mu}\mathrm{SR}$ on single crystals of $\mathrm{Sr}{\mathrm{Mg}}_{0.05}{\mathrm{Cu}}_{1.95}{(\mathrm{B}{\mathrm{O}}_{3})}_{2}$, ${\mathrm{Sr}}_{0.96}{\mathrm{La}}_{0.04}{\mathrm{Cu}}_{2}{(\mathrm{B}{\mathrm{O}}_{3})}_{2}$, and ${\mathrm{Sr}}_{0.95}{\mathrm{Na}}_{0.05}{\mathrm{Cu}}_{2}{(\mathrm{B}{\mathrm{O}}_{3})}_{2}$. We have found that the frequency shifts of these doped samples are equivalent and contain three branches at low temperatures. Two of these branches map onto the branches observed in the pure sample, and so we attribute the third branch to a dopant effect. Specifically, this third branch represents the case when the muon resides at a site in the superexchange path where a local singlet cannot form due to doping. This leads to the conclusion that doping this system both in and out of the $\mathrm{Cu}\mathrm{B}{\mathrm{O}}_{3}$ planes prevents the formation of some singlets.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.020 | 0.002 |
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".