Mapping Nanoscale Metal-Insulator Phase Transition in NdNiO3 and Molecular Beam Epitaxy of SmTiO3 Thin Films
Bibliographic record
Abstract
The subject of this thesis is the growth and characterization of quantum materials. Quantum materials are those in which correlated electron interactions result in functional emergent\nproperties like high-temperature superconductivity, colossal magnetoresistance, ferromagnetism, and metal-insulator transitions. 3d transition metal oxides, particularly perovskites,\nhave been found to be a fertile area of investigation in quantum materials. Rare earth nickelates and titanates fall into this category and are examined here. The bulk of this work\nconcerns soft x-ray spectroscopy and imaging of a free-standing NdNiO3 thin film. NdNiO3\ndisplays a metal-insulator transition as well as a magnetic transition, with the respective\nCurie and Néel temperatures coinciding.\nWe employ x-ray absorption spectroscopy to characterize the electronic transition from\nmetallic to insulating on cooling the sample, noting the magnitude of the hysteresis in the\nprocess; x-ray magnetic scattering to characterize the magnetic transition on heating; and\nscanning transmission x-ray spectromicroscopy to search for the formation of distinct domains of metallic and insulating phases during the progress of the electronic phase transition.\nAlthough these electronic domains were not observed, the sum of our experiments present\nconfirmation that freestanding films of this novel configuration possess similar magnetic and\nelectronic properties to those observed in their bulk counterparts. This finding is significant\nas it indicates that films of this type could be integrated into device applications in the same\nmanner as bulk nickelates.\nA secondary thrust of this work is the development of the capability to synthesize thin\nfilms by molecular beam epitaxy (MBE) at the Canadian Light Source for future studies of\nquantum materials with an emphasis on interface effects and heterostructures. We briefly\npresent results of an effort to grow SmTiO3 thin films by MBE with characterization by\nelectron diffraction and spectroscopy.
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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".