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Abstract Ultrathin epitaxial films of ferromagnetic insulators (FMIs) with Curie temperatures near room temperature are critically needed for use in dissipationless quantum computation and spintronic devices. However, such materials are extremely rare. Here, a room‐temperature FMI is achieved in ultrathin La0.9Ba0.1MnO3films grown on SrTiO3substrates via an interface proximity effect. Detailed scanning transmission electron microscopy images clearly demonstrate that MnO6octahedral rotations in La0.9Ba0.1MnO3close to the interface are strongly suppressed. As determined from in situ X‐ray photoemission spectroscopy, OK‐edge X‐ray absorption spectroscopy, and density functional theory, the realization of the FMI state arises from a reduction of Mn egbandwidth caused by the quenched MnO6octahedral rotations. The emerging FMI state in La0.9Ba0.1MnO3together with necessary coherent interface achieved with the perovskite substrate gives very high potential for future high performance electronic devices.
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Atomic‐Scale Control of Electronic Structure and Ferromagnetic Insulating State in Perovskite Oxide Superlattices by Long‐Range Tuning of BO 6 Octahedra
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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- Award ID(s):
- 1565822
- PAR ID:
- 10641197
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 30
- Issue:
- 40
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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