Evidence of ferromagnetically coupled<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Nd</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>ion pairs in weakly doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi><mml:mi mathvariant="normal">d</mml:mi><mml:mo>:</mml:mo><mml:mi mathvariant="normal">L</mml:mi><mml:mi mathvariant="normal">i</mml:mi><mml:mi mathvariant="normal">Y</mml:mi><mml:mi mathvariant="normal">F</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi><mml:mi mathvariant="normal">d</mml:mi><mml:mo>:</mml:mo><mml:mi mathvariant="normal">Y</mml:mi><mml:mi mathvariant="normal">V</mml:mi><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>crystals as revealed by high-resolution optical and EPR spectroscopies
Bibliographic record
Abstract
Electron paramagnetic resonance (EPR) and high-resolution fluorescence spectra of ${\mathrm{Nd}}^{3+}$ ions in weakly doped ${\mathrm{LiYF}}_{4}$ and ${\mathrm{YVO}}_{4}$ crystals are analyzed. A simple model, based on an effective spin-Hamiltonian approach is proposed to explain the general features of the EPR and optical neodymium spectra in these matrices. Pairs of satellite lines whose intensities grow with neodymium content are observed on each side of the main EPR signals of isolated ${\mathrm{Nd}}^{3+}$ ions. These satellites are assigned to ${\mathrm{Nd}}^{3+}{\ensuremath{-}\mathrm{N}\mathrm{d}}^{3+}$ ion pairs coupled by magnetic dipolar interaction. The calculated Nd-Nd distances are found to be in good agreement with the ${\mathrm{Y}}^{3+}{\ensuremath{-}\mathrm{Y}}^{3+}$ distances in ${\mathrm{LiYF}}_{4}$ and ${\mathrm{YVO}}_{4}$ hosts. The concentration-dependent satellites accompanying the neodymium ${}^{4}{\stackrel{\ensuremath{\rightarrow}}{{F}_{3/2}}}^{4}{I}_{9/2}$ transition are quantitatively explained as being due to several types of ferromagnetically coupled pairs of ${\mathrm{Nd}}^{3+}$ ions, each ion of a pair being located at the regular ${\mathrm{Y}}^{3+}$ site with ${S}_{4}$ and ${D}_{2d}$ point symmetry in ${\mathrm{LiYF}}_{4}$ and ${\mathrm{YVO}}_{4},$ respectively. The exchange coupling values J are found in the range +0.8 to +4.9 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. From literature data, it appears that such ferromagnetically coupled ${\mathrm{Nd}}^{3+}$ pairs with $J=+3{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ also quantitatively explain the optical satellite structure in ${\mathrm{N}\mathrm{d}:\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ (YAG).
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.019 | 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".