Ultrafast optical probes of polaron dynamics in La0.7 Ca0.3 MnO3 thin films

Kaung-Hsiung Wu; T. Y. Hsu; H. C. Shih; Y. J. Chen; Chih-Wei Luo; T. M. Uen; Jiunn-Yuan Lin; Jenh-Yih Juang; T. Kobayashi

doi:10.1063/1.3078082

Ultrafast optical probes of polaron dynamics in La_0.7 Ca_0.3 MnO₃ thin films

Kaung-Hsiung Wu, T. Y. Hsu, H. C. Shih, Y. J. Chen, Chih-Wei Luo, T. M. Uen, Jiunn-Yuan Lin, Jenh-Yih Juang, T. Kobayashi

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Abstract

In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La0.7 Ca0.3 MnO3 (LCMO) thin films. The temporal evolution in transient reflectivity change ΔR/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.

Original language	English
Article number	043901
Journal	Journal of Applied Physics
Volume	105
Issue number	4
DOIs	https://doi.org/10.1063/1.3078082
State	Published - 9 Mar 2009

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title = "Ultrafast optical probes of polaron dynamics in La0.7 Ca0.3 MnO3 thin films",

abstract = "In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La0.7 Ca0.3 MnO3 (LCMO) thin films. The temporal evolution in transient reflectivity change ΔR/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.",

author = "Kaung-Hsiung Wu and Hsu, {T. Y.} and Shih, {H. C.} and Chen, {Y. J.} and Chih-Wei Luo and Uen, {T. M.} and Jiunn-Yuan Lin and Jenh-Yih Juang and T. Kobayashi",

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doi = "10.1063/1.3078082",

language = "English",

volume = "105",

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T1 - Ultrafast optical probes of polaron dynamics in La0.7 Ca0.3 MnO3 thin films

AU - Wu, Kaung-Hsiung

AU - Hsu, T. Y.

AU - Shih, H. C.

AU - Chen, Y. J.

AU - Luo, Chih-Wei

AU - Uen, T. M.

AU - Lin, Jiunn-Yuan

AU - Juang, Jenh-Yih

AU - Kobayashi, T.

PY - 2009/3/9

Y1 - 2009/3/9

N2 - In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La0.7 Ca0.3 MnO3 (LCMO) thin films. The temporal evolution in transient reflectivity change ΔR/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.

AB - In this work, we use ultrafast optical pump-optical probe spectroscopy to probe the polaron dynamics in La0.7 Ca0.3 MnO3 (LCMO) thin films. The temporal evolution in transient reflectivity change ΔR/R exhibits two relaxing components: a fast component with a time constant of subpicosecond and a slow component with time constant ranging from tens of picoseconds to hundreds of picoseconds. The amplitude of the fast component, though has been seldom discussed before, exhibits the similar temperature dependence with that of the resistivity and the neutron scattering intensity due to nanoscale correlated polarons. The results strongly suggest that the fast photoinduced reflectivity change may have been due to the photoexcitation and trapping process of correlated Jahn-Teller polarons in the paramagnetic and ferromagnetic phases and, thus, implies the presence of electronic inhomogeneity in LCMO manganites.

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U2 - 10.1063/1.3078082

DO - 10.1063/1.3078082

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VL - 105

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 4

M1 - 043901

ER -

Ultrafast optical probes of polaron dynamics in La_0.7 Ca_0.3 MnO₃ thin films

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