Ultrafast Optical and Magneto-Optical Dynamics {in Colossal-Magnetoresistance Manganites}

V. Dorosinetsa,b, P. Richtera, G. Jakobc and H.G. Roskos a aPhysikalisches Institut, J.W. Goethe-Universität, Frankfurt/Main 60054, Germany bDepartment of Semiconductor Physics, Belorussian State University, Minsk 220050, Republic of Belarus cInstitut für Physik, J. Gutenberg-Universität Mainz, Mainz 60054, Germany

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Received: 22 08 2004;

Transient pump-probe reflectance measurements on La0.67Ca0.33MnO3/MgO and La0.67 Ca0.33MnO3/SrTiO3 thin films reveal a hitherto unknown magnetization-dependent energy gap that determines the relaxation process of the optically excited charge carriers on the picosecond time scale. In the case of La0.67Ca0.33MnO3/SrTiO3, the subsequent reflectance dynamics at low temperatures is determined to be substrate-induced strain that drives the sample into a metastable state characterized by an increased number of paramagnetic domains.

DOI: 10.12693/APhysPolA.107.211 PACS numbers:78.47.+p