Absolute values of the London penetration depth in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>6</mml:mn><mml:mo>+</mml:mo><mml:mi>y</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>measured by zero field ESR spectroscopy on Gd doped single crystals
Bibliographic record
Abstract
Zero-field electron spin resonance (ESR) of dilute Gd ions substituted for Y in the cuprate superconductor ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+y}$ is used as a novel technique for measuring the absolute value of the low-temperature magnetic penetration depth $\ensuremath{\lambda}(\stackrel{\ensuremath{\rightarrow}}{T}0).$ The Gd ESR spectrum of samples with $\ensuremath{\approx}1%$ substitution was obtained with a broadband microwave technique that measures power absorption bolometrically from 0.5 to 21 GHz. This ESR spectrum is determined by the crystal field that lifts the level degeneracy of the spin $7/2{\mathrm{Gd}}^{3+}$ ion and details of this spectrum provide information concerning oxygen ordering in the samples. The magnetic penetration depth is obtained by relating the number of Gd ions exposed to the microwave magnetic field to the frequency-integrated intensity of the observed ESR transitions. This technique has allowed us to determine precise values of $\ensuremath{\lambda}$ for screening currents flowing in the three crystallographic orientations $(\^a,$ $\mathrm{b\ifmmode \hat{}\else \^{}\fi{}},$ and $\ifmmode \hat{c}\else \^{c}\fi{})$ in samples of ${\mathrm{Gd}}_{x}{\mathrm{Y}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+y}$ of three different oxygen contents $y=0.993{(T}_{c}=89\mathrm{K}),$ $y=0.77{(T}_{c}=75\mathrm{K}),$ and $y=0.52{(T}_{c}=56\mathrm{K}).$ The in-plane values are found to depart substantially from the widely reported relation ${T}_{c}\ensuremath{\propto}1/{\ensuremath{\lambda}}^{2}.$
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.104 | 0.036 |
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".