Suppression of molecular field by lattice contraction in face-centered-cubic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi><mml:msub><mml:mi>Ni</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:mi>Cd</mml:mi></mml:mrow></mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>(</mml:mo><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mi>Ce</mml:mi><mml:mo>,</mml:mo><mml:mo> </mml:mo><mml:mi>Nd</mml:mi><mml:mo>,</mml:mo><mml:mo> </mml:mo><mml:mi>Sm</mml:mi><mml:mo>,</mml:mo><mml:mo> </mml:mo><mml:mtext>and</mml:mtext><mml:mo> </mml:mo><mml:mi>Gd</mml:mi><mml:mo>–</mml:mo><mml:mi>Tm</mml:mi><mml:mo>)</mml:mo></mml:math>
Bibliographic record
Abstract
Single crystals of $R{\mathrm{Ni}}_{4}\mathrm{Cd}$ $(R$ = Ce, Nd, Sm, and $\mathrm{Gd}\ensuremath{-}\mathrm{Tm})$ are grown by Cd flux and their physical properties are investigated by means of x-ray diffraction, magnetization, electrical resistivity, and specific heat measurements. Except for $R=\mathrm{Ce}$, the unit cell volume of $R{\mathrm{Ni}}_{4}\mathrm{Cd}$ follows a lanthanide contraction, implying a $3+$ valence state of rare-earth ions in this series. At high temperatures, magnetic susceptibility curves for $R=\mathrm{Nd}$ and Gd--Tm follow the Curie-Weiss behavior. The obtained Curie-Weiss temperature $({\ensuremath{\theta}}_{p})$ for $R=\mathrm{Gd}\text{--}\mathrm{Tm}$ is small and negative. The temperature dependence of the electrical resistivity shows a metallic behavior for all $R{\mathrm{Ni}}_{4}\mathrm{Cd}$ compounds. Of the thermodynamic and transport property measurements, only ${\mathrm{GdNi}}_{4}\mathrm{Cd}$ indicates an antiferromagnetic ordering below ${T}_{N}=4.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, while the remaining compounds show no signature of magnetic transition down to 1.8 K. The Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange mechanism is examined for its relevance to ${T}_{N}$ and ${\ensuremath{\theta}}_{p}$ of isostructural metallic $R{T}_{4}X$ $(R=\mathrm{Gd}\text{--}\mathrm{Tm}$, $T=\mathrm{Cu} \mathrm{and} \mathrm{Ni}, \mathrm{and} X=\mathrm{Cd}, \mathrm{In}, \mathrm{Mg}, \mathrm{Pd}, \mathrm{Ag}, \mathrm{and} \mathrm{Au})$ compounds. Although the variation in ${\ensuremath{\theta}}_{p}$ can be qualitatively explained by the RKKY sum, the values of ${\ensuremath{\theta}}_{p}$ in this family are highly dependent on their lattice parameter. Unlike the $R{\mathrm{Cu}}_{4}X$, the strength of the exchange interaction between molecular fields produced by rare-earth planes is strongly suppressed by the lattice contraction in $R{\mathrm{Ni}}_{4}X$ compounds.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.015 | 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".