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Abstract Control of BO6octahedral rotations at the heterointerfaces of dissimilar ABO3perovskites has emerged as a powerful route for engineering novel physical properties. However, its impact length scale is constrained at 2–6 unit cells close to the interface and the octahedral rotations relax quickly into bulk tilt angles away from interface. Here, a long‐range (up to 12 unit cells) suppression of MnO6octahedral rotations in La0.9Ba0.1MnO3through the formation of superlattices with SrTiO3can be achieved. The suppressed MnO6octahedral rotations strongly modify the magnetic and electronic properties of La0.9Ba0.1MnO3and hence create a new ferromagnetic insulating state with enhanced Curie temperature of 235 K. The emergent properties in La0.9Ba0.1MnO3arise from a preferential occupation of the out‐of‐plane Mnd3z2−r2orbital and a reduced Mn egbandwidth, induced by the suppressed octahedral rotations. The realization of long‐range tuning of BO6octahedra via superlattices can be applicable to other strongly correlated perovskites for exploring new emergent quantum phenomena.
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Designing Optimal Perovskite Structure for High Ionic Conduction
Abstract Solid‐oxide fuel/electrolyzer cells are limited by a dearth of electrolyte materials with low ohmic loss and an incomplete understanding of the structure–property relationships that would enable the rational design of better materials. Here, using epitaxial thin‐film growth, synchrotron radiation, impedance spectroscopy, and density‐functional theory, the impact of structural parameters (i.e., unit‐cell volume and octahedral rotations) on ionic conductivity is delineated in La0.9Sr0.1Ga0.95Mg0.05O3–δ. As compared to the zero‐strain state, compressive strain reduces the unit‐cell volume while maintaining large octahedral rotations, resulting in a strong reduction of ionic conductivity, while tensile strain increases the unit‐cell volume while quenching octahedral rotations, resulting in a negligible effect on the ionic conductivity. Calculations reveal that larger unit‐cell volumes and octahedral rotations decrease migration barriers and create low‐energy migration pathways, respectively. The desired combination of large unit‐cell volume and octahedral rotations is normally contraindicated, but through the creation of superlattice structures both expanded unit‐cell volume and large octahedral rotations are experimentally realized, which result in an enhancement of the ionic conductivity. All told, the potential to tune ionic conductivity with structure alone by a factor of ≈2.5 at around 600 °C is observed, which sheds new light on the rational design of ion‐conducting perovskite electrolytes.
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- Award ID(s):
- 1708615
- PAR ID:
- 10367706
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 32
- Issue:
- 1
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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