Three‐dimensional micromagnetic modeling of randomly oriented magnetite grains (0.03–0.3 <i>μ</i>m)
Bibliographic record
Abstract
We report three‐dimensional micromagnetic structures obtained for magnetite cubes with 〈100〉 edges in the size range 0.03–0.3 μm around the single‐domain threshold size. We employed the Metropolis algorithm to find equilibrium micromagnetic structures starting from uniformly magnetized initial states. Directions of initial magnetizations were randomly set so as to mimic a randomly oriented assemblage. Small grains (<0.07 μm) exhibit single‐domain equilibrium structures parallel to a magnetic easy axis 〈111〉 irrespective of initial magnetization directions. Vortex structures emerge for small pseudosingle‐domain grains above 0.07 μm. Axes of the vortices are parallel to 〈100〉 in the threshold size range but become randomly oriented with increasing grain size. Neither lamellar domain structures nor multiple vortex structures were found for grains smaller than 0.3 μm. Reduced saturation remanent magnetization decreased down to ∼0.1 with increasing grain size over a relatively narrow grain size range (0.07–0.15 μm). The grain size variation of reduced magnetization depends on microscopic magnetization structures inside a single grain and the degree of randomness of grain magnetization directions in an assemblage.
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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 | 0.001 | 0.000 |
| Open science | 0.001 | 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".