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Bibliographic record
Abstract
The synthesis, structural, and magnetic characterization of the series ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{La}}_{1+x}\mathrm{Mn}{\mathrm{O}}_{4+\ensuremath{\delta}}$ ($0\ensuremath{\le}x\ensuremath{\le}0.5$) with the ${\mathrm{K}}_{2}\mathrm{Ni}{\mathrm{F}}_{4}$-type structure are reported. We previously found that the $x=0.2$ member exhibits the very rare anisotropic spin-glass behavior with only the $c$-axis spin component freezing below ${T}_{\mathrm{g}}$. Here we show that each member of the ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{La}}_{1+x}\mathrm{Mn}{\mathrm{O}}_{4+\ensuremath{\delta}}$ ($0\ensuremath{\le}x\ensuremath{\le}0.4$) series exhibits the same spin-glass behavior. Moreover, ${T}_{\mathrm{g}}$ varies with $x$, reaching a maximum of 26.4(4) K for $x=0.20$ compared with 19.2(2) K for $x=0$. The spin-glass behavior was confirmed by both dc and ac magnetic susceptibility measurements. No long-range magnetic order was found down to 2 K. All series members adopt the $I4/mmm$ space group and subtle structural transformations occur with increasing La content. The unit cell volume contracts for $0.0<x<0.3$ and expands for $0.3<x\ensuremath{\le}0.5$. Similar behavior is seen for the equatorial Mn-O bonds in the Mn-O octahedron while the axial Mn-O distances increase to $x\ensuremath{\sim}0.3$ but remain unchanged for higher $x$. X-ray absorption near-edge structure analysis revealed that the oxidation state of Mn in the ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{La}}_{1+x}\mathrm{Mn}{\mathrm{O}}_{4+\ensuremath{\delta}}$ samples varies with $x$: For $x\ensuremath{\le}0.2$ Mn is in the +3.0(1) oxidation state only, while for $x>0.2$ a mixed +2/+3 oxidation state was found. Therefore, for the charge balance, samples with $x\ensuremath{\le}0.2$ contain excess oxygen as an interstitial species, while for $x>0.2$, the structure cannot sustain any more interstitial oxygen and the La excess is accommodated through the reduction of some ${\mathrm{Mn}}^{3+}$ to ${\mathrm{Mn}}^{2+}$. Based on the oxidation state of Mn, the possible origins of the spin-glass magnetism in the ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{La}}_{1+x}\mathrm{Mn}{\mathrm{O}}_{4+\ensuremath{\delta}}$ series are discussed.
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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 | 0.008 | 0.007 |
| Meta-epidemiology (narrow) | 0.005 | 0.011 |
| Meta-epidemiology (broad) | 0.002 | 0.010 |
| Bibliometrics | 0.003 | 0.007 |
| Science and technology studies | 0.007 | 0.008 |
| Scholarly communication | 0.008 | 0.007 |
| Open science | 0.011 | 0.011 |
| Research integrity | 0.009 | 0.008 |
| Insufficient payload (model declined to judge) | 0.919 | 0.013 |
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; both teacher heads agree on what is shown here.
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".