Spark plasma sintered Ce/Gd co‐doped lanthanum hexaboride with enhanced thermionic emission properties
Bibliographic record
Abstract
Abstract This study investigates the effect of Ce/Gd co‐doping on the work function and thermionic emission properties of lanthanum hexaboride (LaB 6 ). Density functional theory calculations demonstrate that the Ce/Gd co‐doping effectively reduces the work function of LaB 6 , with the value decreasing from 2.11 eV for the LaB 6 (100) surface to 2.09 eV for the La 0.5 Ce 0.25 Gd 0.25 B 6 (100) surface. Using spark plasma sintering, Ce/Gd co‐doped LaB 6 bulks with a CsCl‐type single‐phase substitutional solid solution structure were fabricated, achieving relative densities exceeding 96.2%. The dense SPSed specimens exhibit no noticeable texture, comparable average grain size, and a homogeneous distribution of rare‐earth metal cations. The H v value of 21.2 ± 0.54 GPa for La 0.5 Ce 0.25 Gd 0.25 B 6 is higher than that of 18.5 ± 0.60 GPa for LaB 6 , which can be ascribed to the solid solution strengthening effect induced by Ce/Gd co‐doping; however, the Ce/Gd co‐doping is incapable of improving fracture toughness. Ultraviolet photoelectron spectroscopy analysis further confirms that the work function of Ce/Gd co‐doped LaB 6 (2.58 eV for La 0.5 Ce 0.25 Gd 0.25 B 6 ) is lower than that of pure LaB 6 (2.68 eV). Importantly, under identical operating conditions, the dense La 0.5 Ce 0.25 Gd 0.25 B 6 bulk demonstrates higher thermionic emission current densities than LaB 6 , highlighting its promising potential as a high‐performance thermionic cathode material.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".