Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 19: Magnetic Half-metals and Oxides II

MA 19.1: Vortrag

Mittwoch, 24. März 2010, 15:15–15:30, H22

Phase diagram of (La_1−yPr_y)_0.67Ca_0.33MnO₃ thin films: structural, magnetic and transport data — •Sebastian Hühn, Camillo Ballani, Markus Jungbauer, Kai Gehrke, Vasily Moshnyaga, and Konrad Samwer — 1. Physikalisches Institut, Universität Göttingen

Colossal magnetoresistance (CMR) has been extensively studied in prototypic (La_1−yPr_y)_0.67Ca_0.33MnO₃ (LPCMO) bulk material [1], in which Pr substitution (y) provides a way to control the electron-lattice coupling. CMR was discussed within disorder induces phase separation scenario and percolative metal insulator transition [2]. Here we try to get more reliable information on the CMR physics on epitaxial strain-free LPCMO films (single crystals are not available). We prepared LPCMO films on MgO(100) substrates by metalorganic aerosol deposition technique. The structure was studied by X-ray diffraction. Magnetization and resistivity were measured as a function of temperature, T=10−300K, and magnetic field, B=0−7 T. With these data, we were able to create a phase diagram for LPCMO films and to observe hysteretic temperature and magnetic field behavior as well as the influence of cation ordering. Support by Deutsche Forschungsgemeinschaft via SFB 602, TP A2 is acknowledged.

[1] M. Uehara, S. Mori, C.H. Chen, S.-W. Cheong "Percolative phase separation underlies colossal magnetoresistance in mixed-valent manganites" Nature, 399:560, 1999

[2] Elbio Dagotto. "Nanoscale Phase Separation and Colossal Magnetoresistance" Spinger-Verlag, 2002