Topotactic Reduction‐Driven Crystal Field Excitations in Brownmillerite Manganite Thin Films

Abstract Topotactic reduction of perovskite oxides offers a powerful approach for discovering novel phenomena, such as superconducting infinite‐layer nickelates and polar metallicity, and is commonly accompanied by the emergence of multiple valence states and/or complex crystal fields of transition metals. However, understanding the complex interplay between crystal chemistry, electronic structure, and physical properties at the spin‐ and orbital‐resolved levels in these reduced systems remains elusive. Here, x‐ray absorption spectroscopy, resonant inelastic x‐ray scattering (RIXS), and density functional theory calculations are used to uncover topotactic metal‐insulator transition and orbital‐specific crystal field excitations in brownmillerite La 0.67 Ca 0.33 MnO 2.5 thin films. The Mn valence states are found to be Mn 2+ /Mn 3+ , along with their corresponding populations at octahedral and tetrahedral sites, which effectively weaken the Mn‐O hybridization compared to the parent perovskite phase. As a result, La 0.67 Ca 0.33 MnO 2.5 films exhibit an antiferromagnetic insulating ground state. Moreover, by combining the RIXS measurements on selected single‐valence manganites, specifically MnO, LaMnO 3 , and CaMnO 3 , with orbital‐ and spin‐resolved density‐of‐states calculations, the study identifies the dd excitations of octahedrally and tetrahedrally coordinated Mn 2+ /Mn 3+ ions, directly linking the microscopic electronic structure to the macroscopic magnetic/electrical properties.

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Publication Details

Journal
Advanced Functional Materials
Published
2025-02-19
DOI
https://doi.org/10.1002/adfm.202501893
Citations
2
Primary Topic
Magnetic and transport properties of perovskites and related materials
Type
article
Field-Weighted Citation Impact
0.85

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article

Topotactic Reduction‐Driven Crystal Field Excitations in Brownmillerite Manganite Thin Films

Zixun Zhang, V. K. Bhartiya, Jingdi Lu, Shiyu Fan et al.
2 citations
Advanced Functional Materials
Magnetic and transport properties of perovskites and related materials
0.85
article

Topotactic Reduction‐Driven Crystal Field Excitations in Brownmillerite Manganite Thin Films

Zixun Zhang, V. K. Bhartiya, Jingdi Lu, Shiyu Fan, Mingqiang Gu, Jonathan Pelliciari, Qiming Lv, Valentina Bisogni, Zhen Huang, Taehun Kim, Jinfeng Zhang, Feng Jin, Lingfei Wang, Wenbin Wu, Min Ge
article en
2 citations

Abstract

Abstract Topotactic reduction of perovskite oxides offers a powerful approach for discovering novel phenomena, such as superconducting infinite‐layer nickelates and polar metallicity, and is commonly accompanied by the emergence of multiple valence states and/or complex crystal fields of transition metals. However, understanding the complex interplay between crystal chemistry, electronic structure, and physical properties at the spin‐ and orbital‐resolved levels in these reduced systems remains elusive. Here, x‐ray absorption spectroscopy, resonant inelastic x‐ray scattering (RIXS), and density functional theory calculations are used to uncover topotactic metal‐insulator transition and orbital‐specific crystal field excitations in brownmillerite La 0.67 Ca 0.33 MnO 2.5 thin films. The Mn valence states are found to be Mn 2+ /Mn 3+ , along with their corresponding populations at octahedral and tetrahedral sites, which effectively weaken the Mn‐O hybridization compared to the parent perovskite phase. As a result, La 0.67 Ca 0.33 MnO 2.5 films exhibit an antiferromagnetic insulating ground state. Moreover, by combining the RIXS measurements on selected single‐valence manganites, specifically MnO, LaMnO 3 , and CaMnO 3 , with orbital‐ and spin‐resolved density‐of‐states calculations, the study identifies the dd excitations of octahedrally and tetrahedrally coordinated Mn 2+ /Mn 3+ ions, directly linking the microscopic electronic structure to the macroscopic magnetic/electrical properties.

Advanced Functional MaterialsVol. 35(28)
University of Science and Technology of China (CN), Anhui University (CN), Sun Yat-sen University (CN), Chinese Academy of Sciences (CN), Brookhaven National Laboratory (US), Hefei Institutes of Physical Science (CN), Southern University of Science and Technology (CN), High Magnetic Field Laboratory (CN), Hefei National Center for Physical Sciences at Nanoscale (CN)
Guangdong Innovative and Entrepreneurial Research Team Program, National Natural Science Foundation of China, Natural Science Foundation of Guangdong Province, Natural Science Foundation of Anhui Province, National Key Research and Development Program of China
Openalex Percentile: Top 30%
Magnetic and transport properties of perovskites and related materials
0.85
DOIOpen Access PDFOpenAlex
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