Picosecond dynamics in layered cobalt perovskites studied by time-resolved Raman spectroscopy

Ryo Fukaya; Nao Yamaya; Tadahiko Ishikawa; Shin Ya Koshihara; Yoichi Okimoto; Ken Onda; Akira Isayama; Takao Sasagawa; Kazumasa Horigane

doi:10.5802/CRPHYS.35

Picosecond dynamics in layered cobalt perovskites studied by time-resolved Raman spectroscopy

Ryo Fukaya, Nao Yamaya, Tadahiko Ishikawa, Shin Ya Koshihara, Yoichi Okimoto, Ken Onda, Akira Isayama, Takao Sasagawa, Kazumasa Horigane

Research Institute for Interdisciplinary Science

Research output: Contribution to journal › Article › peer-review

Abstract

Picosecond dynamics of the photoexcited charge-ordered perovskite-type cobalt oxides La_1.5Ca_0.5CoO₄ and La_1.5Sr_0.5CoO₄ were investigated based on time-resolved Raman and reflection spectroscopy. These cobalt oxides show strong Raman scattering at around 700 cm^-1, originating from the breathing vibration mode of the CoO₆ octahedron coupled with the checkerboard-type charge ordering of Co²⁺ and Co³⁺. We performed time-resolved Raman and reflection spectroscopy by photoirradiating with picosecond pulses at 400 nm, exciting the charge transfer (CT) transition from the O 2p site to the Co 3d site. As a result of the excitation, the Raman intensity of the breathing mode was suppressed by 10% on a similar time scale in the reflectance change without changing the frequency of the mode, directly indicating ultrafast suppression of the order parameter of the charge-ordered state by CT transition.

Original language	English
Journal	Comptes Rendus Physique
Volume	22
DOIs	https://doi.org/10.5802/CRPHYS.35
Publication status	Published - 2021

Keywords

Femtosecond technology
Perovskite-type oxide
Raman spectroscopy
Spin crossover cobaltite
Time-resolved spectroscopy

ASJC Scopus subject areas

Physics and Astronomy(all)

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10.5802/CRPHYS.35

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@article{1b180f4cf4a7459884a8bcb07a59773b,

title = "Picosecond dynamics in layered cobalt perovskites studied by time-resolved Raman spectroscopy",

abstract = "Picosecond dynamics of the photoexcited charge-ordered perovskite-type cobalt oxides La1.5Ca0.5CoO4 and La1.5Sr0.5CoO4 were investigated based on time-resolved Raman and reflection spectroscopy. These cobalt oxides show strong Raman scattering at around 700 cm-1, originating from the breathing vibration mode of the CoO6 octahedron coupled with the checkerboard-type charge ordering of Co2+ and Co3+. We performed time-resolved Raman and reflection spectroscopy by photoirradiating with picosecond pulses at 400 nm, exciting the charge transfer (CT) transition from the O 2p site to the Co 3d site. As a result of the excitation, the Raman intensity of the breathing mode was suppressed by 10% on a similar time scale in the reflectance change without changing the frequency of the mode, directly indicating ultrafast suppression of the order parameter of the charge-ordered state by CT transition.",

keywords = "Femtosecond technology, Perovskite-type oxide, Raman spectroscopy, Spin crossover cobaltite, Time-resolved spectroscopy",

author = "Ryo Fukaya and Nao Yamaya and Tadahiko Ishikawa and Koshihara, {Shin Ya} and Yoichi Okimoto and Ken Onda and Akira Isayama and Takao Sasagawa and Kazumasa Horigane",

note = "Funding Information: The authors thank H. Taniguchi and M. Itoh for the early stage of this work concerning Raman spectroscopy and T. Egawa, K. Yu, H. Matsushima, and S. Tanaka for their technical assistance. This research was supported by JSPS KAKENHI Grant No. 19H01827, 18H05208, 16H04000, JP17H06375, JP18H05170. Publisher Copyright: {\textcopyright} 2021 Elsevier Masson SAS. All rights reserved.",

year = "2021",

doi = "10.5802/CRPHYS.35",

language = "English",

volume = "22",

journal = "Comptes Rendus Physique",

issn = "1631-0705",

publisher = "Elsevier Masson",

}

TY - JOUR

T1 - Picosecond dynamics in layered cobalt perovskites studied by time-resolved Raman spectroscopy

AU - Fukaya, Ryo

AU - Yamaya, Nao

AU - Ishikawa, Tadahiko

AU - Koshihara, Shin Ya

AU - Okimoto, Yoichi

AU - Onda, Ken

AU - Isayama, Akira

AU - Sasagawa, Takao

AU - Horigane, Kazumasa

N1 - Funding Information: The authors thank H. Taniguchi and M. Itoh for the early stage of this work concerning Raman spectroscopy and T. Egawa, K. Yu, H. Matsushima, and S. Tanaka for their technical assistance. This research was supported by JSPS KAKENHI Grant No. 19H01827, 18H05208, 16H04000, JP17H06375, JP18H05170. Publisher Copyright: © 2021 Elsevier Masson SAS. All rights reserved.

PY - 2021

Y1 - 2021

N2 - Picosecond dynamics of the photoexcited charge-ordered perovskite-type cobalt oxides La1.5Ca0.5CoO4 and La1.5Sr0.5CoO4 were investigated based on time-resolved Raman and reflection spectroscopy. These cobalt oxides show strong Raman scattering at around 700 cm-1, originating from the breathing vibration mode of the CoO6 octahedron coupled with the checkerboard-type charge ordering of Co2+ and Co3+. We performed time-resolved Raman and reflection spectroscopy by photoirradiating with picosecond pulses at 400 nm, exciting the charge transfer (CT) transition from the O 2p site to the Co 3d site. As a result of the excitation, the Raman intensity of the breathing mode was suppressed by 10% on a similar time scale in the reflectance change without changing the frequency of the mode, directly indicating ultrafast suppression of the order parameter of the charge-ordered state by CT transition.

AB - Picosecond dynamics of the photoexcited charge-ordered perovskite-type cobalt oxides La1.5Ca0.5CoO4 and La1.5Sr0.5CoO4 were investigated based on time-resolved Raman and reflection spectroscopy. These cobalt oxides show strong Raman scattering at around 700 cm-1, originating from the breathing vibration mode of the CoO6 octahedron coupled with the checkerboard-type charge ordering of Co2+ and Co3+. We performed time-resolved Raman and reflection spectroscopy by photoirradiating with picosecond pulses at 400 nm, exciting the charge transfer (CT) transition from the O 2p site to the Co 3d site. As a result of the excitation, the Raman intensity of the breathing mode was suppressed by 10% on a similar time scale in the reflectance change without changing the frequency of the mode, directly indicating ultrafast suppression of the order parameter of the charge-ordered state by CT transition.

KW - Femtosecond technology

KW - Perovskite-type oxide

KW - Raman spectroscopy

KW - Spin crossover cobaltite

KW - Time-resolved spectroscopy

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ER -

Picosecond dynamics in layered cobalt perovskites studied by time-resolved Raman spectroscopy

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