Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Poster Ia: Electron Theory (1); Magnetic Imaging (2,3); Thin Films (4-25); MSMA (26-33); Magn. Semiconductors (34-42); Magn. Half Metals and Oxides (43-60)

MA 13.49: Poster

Tuesday, March 24, 2009, 10:15–13:00, P1A

Optical and magnetooptical studies on manganite films — •Markus Jungbauer, Kai Gehrke, Vasily Moshnyaga, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

The mechanism of the metal-insulator transition and CMR effect in perovskite manganites is still under debates. It was argued that Jahn-Teller polarons and phase separation play an essential role at this point. For further detailed study of these phenomena we built an experimental setup for simultaneous electric transport, optical and magnetooptical measurements on manganite thin films in the range of temperatures 20 K-400 K, magnetic fields up to H_max =15 kOe and photon energies h ν=1.3 eV to 4 eV. Using this setup we studied three different manganite compounds: La_1−xSr_xMnO₃ , La_1−xCa_xMnO₃ and (La_0.6Pr_0.4)_1−xCa_xMnO₃ , epitaxially grown on MgO-substrates using MAD technique. The films were also characterized by X-ray diffraction and scanning tunneling microscopy. Then the optical transmission, faraday-rotation, faraday-ellipticity and coercitivity as a function of temperature and magnetic field were measured. The magnetic and electronic phase transition were visualized in optics and magnetooptics and compared with magnetotransport data.

Deutsche Forschungsgemeinschaft via SFB 602, TPA2 is acknowledged.