Comparing Magnetism in Isostructural Oxides A0.8La1.2MnO4.1: Anisotropic Spin Glass (A = Ba) Versus Long Range Order (A = Sr)
Bibliographic record
Abstract
This study presents the strikingly distinct magnetic properties of two isostructural compounds, Ba0.8La1.2MnO4.1 and Sr0.8La1.2MnO4.1 (K2NiF4 – type, I4/mmm). Spectroscopic studies have shown that Mn is in a +3.0(1) oxidation state only, in both compounds; therefore, the charge is balanced by accommodating extra oxygen at interstitials sites, as confirmed by neutron powder diffraction. We found that the Ba compound exhibits an exceedingly rare anisotropic spin glass behaviour, Tg = 26.4 K, with the moment freezing along the c-axis only while the in-plane spin components remain dynamic well below Tg. Experimental results including neutron diffraction, heat capacity, and magnetic (dc and ac) measurements performed on an oriented single crystal support this conclusion. This is a remarkable result, the only other known example of an anisotropic spin glass being Fe2TiO5. The spin glass state in Ba0.8La1.2MnO4.1 is argued to arise due to competing antiferromagnetic and ferromagnetic 180º Mn3+−O−Mn3+ superexchange interactions. In contrast, the Sr analogue shows 2D antiferromagnetic correlations and long range antiferromagnetic order below 95 K with a remarkably reduced ordered moment of 1.4 μB/Mn3+ instead of the ~ 4 μB expected for an S = 2 ion.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.003 |
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".