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 output: Contribution to journalArticlepeer-review

    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.

    Original languageEnglish
    JournalComptes Rendus Physique
    Volume22
    DOIs
    Publication statusPublished - 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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