HUSCAP logo Hokkaido Univ. logo

Hokkaido University Collection of Scholarly and Academic Papers >
Research Institute for Electronic Science >
Peer-reviewed Journal Articles, etc >

Unusually Large Thermopower Change from +330 to -185 mu V K-1 of Brownmillerite SrCoO2.5

Files in This Item:
Revised Manuscript ACS Appl. Electron. Mater._clean.pdf2.85 MBPDFView/Open
Please use this identifier to cite or link to this item:

Title: Unusually Large Thermopower Change from +330 to -185 mu V K-1 of Brownmillerite SrCoO2.5
Authors: Yang, Qian Browse this author
Lee, Joonhyuk Browse this author
Feng, Bin Browse this author
Ikuhara, Yuichi Browse this author
Kim, Gowoon Browse this author
Cho, Hai Jun Browse this author
Jeen, Hyoungjeen Browse this author
Ohta, Hiromichi Browse this author →KAKEN DB
Keywords: thermopower
brownmillerite SrCoO2.5
epitaxial film
pulsed laser deposition
electronic structure
Issue Date: 28-Jul-2020
Publisher: American Chemical Society
Journal Title: ACS Applied Electronic Materials
Volume: 2
Issue: 7
Start Page: 2250
End Page: 2256
Publisher DOI: 10.1021/acsaelm.0c00427
Abstract: Strontium cobalt oxide (SrCoO2.5) has recently attracted increasing attention as its optoelectronic and magnetic properties can be widely controlled using electrochemical oxidation/protonation at room temperature in air. To utilize the versatile properties of SrCoO2.5, it is essential to evaluate the location of the Fermi energy (E-F) in the electronic structure, which is sensitive to the oxidation state of the Co ions. Here, we show that thermopower is an excellent measure for analyzing the E-F in SrCoO2.5 epitaxial films. The lattice mismatch causes grain size reduction, which induces a slight increase in the oxidation state of the Co ions due to additional adsorbed oxygen. Although X-ray spectroscopy analyses reveal that the difference of the oxidation state of the Co ions among the samples is small, an unusually large change in thermopower from +330 mu V K-1 (lattice-matched) to -185 mu V K-1 (lattice-mismatched) is observed in the samples due to shifts in the E-F to the lower energy side. The present results demonstrate the excellent sensitivity of thermopower measurements for analyzing the location of E-F in the electronic structure of SrCoO(2.3 )in a practically usable environment.
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Electronic Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see .
Type: article (author version)
Appears in Collections:電子科学研究所 (Research Institute for Electronic Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 太田 裕道

Export metadata:

OAI-PMH ( junii2 , jpcoar_1.0 )

MathJax is now OFF:


 - Hokkaido University