Abstract
Topotactic phase transformation enables structural transition without losing the crystalline symmetry of the parental phase and provides an effective platform for elucidating the redox reaction and oxygen diffusion within transition metal oxides. In addition, it enables tuning of the emergent physical properties of complex oxides, through strong interaction between the lattice and electronic degrees of freedom. In this communication, the electronic structure evolution of SrFeOx epitaxial thin films is identified in real-time, during the progress of reversible topotactic phase transformation. Using real-time optical spectroscopy, the phase transition between the two structurally distinct phases (i.e., brownmillerite and perovskite) is quantitatively monitored, and a pressure–temperature phase diagram of the topotactic transformation is constructed for the first time. The transformation at relatively low temperatures is attributed to a markedly small difference in Gibbs free energy compared to the known similar class of materials to date. This study highlights the phase stability and reversibility of SrFeOx thin films, which is highly relevant for energy and environmental applications exploiting the redox reactions.
Original language | English |
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Article number | 1606566 |
Journal | Advanced Materials |
Volume | 29 |
Issue number | 37 |
DOIs | |
State | Published - Oct 4 2017 |
Funding
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and future Planning (NRF-2017R1A2B4011083). This work was also supported by the IBS-R011-D1. J.H. was supported by the National Research Foundation of Korea (NRFK Grant No. 2017R1A2B4007387). M.K., T.D.K., and T.W.N. were supported by the IBS-R009-D1. H.O. was supported by the JSPS-KAKENHI (No. 17H01314, 25106007). This work was also supported in part by the Network Joint Research Center for Materials and Devices.
Funders | Funder number |
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JSPS-KAKENHI | 25106007 |
NRFK | IBS-R009-D1, 2017R1A2B4007387 |
Network Joint Research Center for Materials and Devices | |
Japan Society for the Promotion of Science | 17H01314 |
Ministry of Science, ICT and Future Planning | NRF-2017R1A2B4011083 |
National Research Foundation of Korea |
Keywords
- electronic structures
- optical spectroscopy
- perovskite oxides
- thin films
- topotactic phase transformation