Femtosecond dynamics of the structural transition in mixed valence manganites

We investigate the structural response of charge and orbitally ordered (CO/OO) manganites to ultrafast optical excitation using optical reflectivity and x-ray diffraction as a probe. We study a La0.42Ca0.58MnO3 (LCMO) thin film and a La0.25Pr0.375Ca0.375MnO3 (LPCMO) single crystal. For both materials we observe oscillations in the optical responses that are assigned to a coherent optical phonon generated via displacive excitation. The coherent phonon disappears either when increasing the temperature above T-CO/OO or when raising the excitation fluence above a certain threshold. At low excitation fluences the amplitude and lifetime of this phonon behave similarly to the order parameter of the structural phase transition.


Published in:
Physical Review B, 86, 17
Year:
2012
Publisher:
College Pk, American Physical Society
ISSN:
1098-0121
Laboratories:




 Record created 2013-02-27, last modified 2018-03-17


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