Atomic-Scale Observation of Structure Transition from Brownmillerite to Infinite Layer in SrFeO2.5Thin Films

Zhu，Liang1,2,3; Gao，Lei1; Wang，Lifen1,4; Xu，Zhi1,2,4; Wang，Jianlin1,2; Li，Xiaomin1; Liao，Lei1,2; Huang，Tongtong5; Huang，Hailing1,2; Ji，Ailing1,2; Lu，Nianpeng1,4; Cao，Zexian1,2,4; Li，Qian6; Sun，Ji Rong1,2,4; Yu，Pu5,7; Bai，Xuedong1,2,4

2021

10.1021/acs.chemmater.0c04683

CHEMISTRY OF MATERIALS   影响因子和分区

0897-4756

1520-5002

Stoichiometry modulation in transition-metal perovskite oxides is a pivotal process that can give rise to unprecedented structures and new functionalities. Despite intensive study, the atomic mechanism of the structural transitions occurring in these versatile solid-state ceramics is far from well understood. Here, utilizing in situ electrical biasing (scanning) transmission electron microscopy, we show that the transformation from brownmillerite SrFeO2.5 to infinite-layer SrFeO2 can be directly visualized with atomic resolution. Our observations unveil that the transition process occurring in the cross section thinned film contains two steps. At the initial stage, the tilting of FeO6 octahedra and rotation of the FeO4 tetrahedra due to possible ferroelectricity result in conversion from the mixed structural domains (a|| and b||) to a homogeneous domain (a||) in SrFeO2.5; next, the electric reduced infinite-layer SrFeO2 gradually begins to nucleate at the film/substrate end showing a sharp interface and finally spreads across the entire film. The microscopic kinetics is dominated by the rearrangement of the Fe-O bonding geometry, which occurs through a two-step phase-transition mechanism involving oxygen polyhedral rearrangement, oxygen diffusion, and planar phase formation along the c-axis. This work clarifies the microscopic atomic processes of the oxygen polyhedral rearrangement, oxide ion migration, and the final phase transition from brownmillerite to infinite-layer structure, and offers a new pathway to obtain designed structural materials with specific functionality.

SCI ; EI

英语

其他

WOS:000651524100008

20212210422649

Atoms ; High resolution transmission electron microscopy ; Iron metallography ; Perovskite ; Scanning electron microscopy ; Strontium compounds ; Transition metals

Minerals:482.2 ; Metallurgy and Metallography:531 ; Metallography:531.2 ; Optical Devices and Systems:741.3 ; Atomic and Molecular Physics:931.3

MATERIALS SCIENCE

2-s2.0-85106534766

Scopus

1.Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing,100190,China
2.School of Physical Sciences,University of Chinese Academy of Sciences,Beijing,100190,China
3.Department of Physics,Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices,Southern University of Science and Technology,Shenzhen, Guangdong,518055,China
4.Songshan Lake Materials Laboratory,Dongguan, Guangdong,523808,China
5.State Key Laboratory of Low Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing,100084,China
6.State Key Laboratory of New Ceramics and Fine Processing,School of Materials Science and Engineering,Tsinghua University,Beijing,100084,China
7.Collaborative Innovation Center of Quantum Matter,Beijing,100084,China

Zhu，Liang,Gao，Lei,Wang，Lifen,et al. Atomic-Scale Observation of Structure Transition from Brownmillerite to Infinite Layer in SrFeO2.5Thin Films[J]. CHEMISTRY OF MATERIALS,2021,33:3113-3120.

Zhu，Liang.,Gao，Lei.,Wang，Lifen.,Xu，Zhi.,Wang，Jianlin.,...&Bai，Xuedong.(2021).Atomic-Scale Observation of Structure Transition from Brownmillerite to Infinite Layer in SrFeO2.5Thin Films.CHEMISTRY OF MATERIALS,33,3113-3120.

Zhu，Liang,et al."Atomic-Scale Observation of Structure Transition from Brownmillerite to Infinite Layer in SrFeO2.5Thin Films".CHEMISTRY OF MATERIALS 33(2021):3113-3120.