Structural, Mössbauer, and transport studies of the icosahedral quasicrystals Al<sub>55</sub>Si<sub>7</sub>Cu<sub>25.5</sub>Fe<sub>12.5</sub>, Al<sub>62.5</sub>Cu<sub>24.5</sub>Fe<sub>13</sub>and the crystalline 1/1 approximant Al<sub>55</sub>Si<sub>7</sub>Cu<sub>25.5</sub>Fe<sub>12.5</sub>
Bibliographic record
Abstract
As-quenched icosahedral Al 55 Si 7 Cu 25.5 Fe 12.5 , its 1/1 approximant of the same composition, and icosahedral Al 62.5 Cu 24.5 Fe 13 alloys have been studied using x-ray diffraction, scanning transmission electron microscopy and the high-angle annular dark field technique, zero-field and in-field 57 Fe Mössbauer spectroscopy, and electrical resistivity. The crystal structure of the 1/1 approximant Al 55 Si 7 Cu 25.5 Fe 12.5 has been refined with the Rietveld method and shown to be compatible with the measured high-angle annular dark field images. The distribution of the principal component of the electric field gradient tensor has a bimodal character with a dominant negative sign in the icosahedral Al–Cu–Fe system. The local order of the Fe structural environment is compared in icosahedral Al 55 Si 7 Cu 25.5 Fe 12.5 , its 1/1 approximant, and icosahedral Al 62.5 Cu 24.5 Fe 13 . The average quadrupole splitting decreases with temperature as T 3/2 for all alloys studied, and its value is significantly larger for the icosahedral alloys. The vibrations of the Fe atoms in the alloys studied are well described by a Debye model, with characteristic Mössbauer temperatures of 468(25), 487(19), and 455(6) K for icosahedral Al 55 Si 7 Cu 25.5 Fe 12.5 , its 1/1 approximant, and icosahedral Al 62.5 Cu 24.5 Fe 13 , respectively. The electrical resistivity is discussed in terms of quantum interference effects and structural disorder.
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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 | 0.000 |
| 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) | 0.001 | 0.000 |
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".