Characterization of the spin-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mfrac><mml:mn>1</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math>linear-chain ferromagnet CuAs<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow/><mml:mn>2</mml:mn></mml:msub></mml:math>O<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow/><mml:mn>4</mml:mn></mml:msub></mml:math>
Bibliographic record
Abstract
The magnetic and lattice properties of the $S=1/2$ quantum-spin-chain ferromagnet CuAs${}_{2}$O${}_{4}$, mineral name trippkeite, were investigated. The crystal structure of CuAs${}_{2}$O${}_{4}$ is characterized by the presence of corrugated CuO${}_{2}$ ribbon chains. Measurements of the magnetic susceptibility, heat capacity, electron paramagnetic resonance, and Raman spectroscopy were performed. Our experiments conclusively show that a ferromagnetic transition occurs at $\ensuremath{\sim}$7.4 K. Ab initio DFT calculations reveal dominant ferromagnetic nearest-neighbor and weaker antiferromagnetic next-nearest-neighbor spin exchange interactions along the ribbon chains. The ratio of ${J}_{\mathrm{nn}}$/${J}_{\mathrm{nnn}}$ is near $\ensuremath{-}$4, placing CuAs${}_{2}$O${}_{4}$ in close proximity to a quantum critical point in the ${J}_{\mathrm{nn}}$-${J}_{\mathrm{nnn}}$ phase diagram. TMRG simulations used to analyze the magnetic susceptibility confirm this ratio. Single-crystal magnetization measurements indicate that a magnetic anisotropy forces the Cu${}^{2+}$ spins to lie in an easy plane perpendicular to the $c$ axis. An analysis of the field- and temperature-dependent magnetization by modified Arrott plots reveals a 3d-$X$Y critical behavior. Lattice perturbations induced by quasihydrostatic pressure and temperature were mapped via magnetization and Raman spectroscopy.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".