Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 35: Magnetic Oxides and Shape Memory Alloys (jointly with MM)

MA 35.9: Vortrag

Donnerstag, 14. März 2013, 11:30–11:45, H23

Photoinduced changes of the first and third harmonic voltage at the metal insulator transition — •Christin Kalkert, Marvin Walter, Jakob Walowski, Manuel Mchalwat, Vasily Moshnyaga, Bernd Damaschke, Markus Münzenberg, and Konrad Samwer — I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

Manganite compounds are well known for their sensitivity to different external stimuli such as magnetic and electric fields. This is manifested for example in the colossal magnetoresistance and the colossal electroresistance effect. Here we study the influence of laser light on the first and third harmonic voltage in the vicinity of the temperature dependent metal insulator transition. We prepared epitaxial La_1−xBa_xMnO₃ films (x = 0.2 … 0.3) on SrTiO₃ substrates by metalorganic aerosol depostion technique. The first and third harmonic voltages were measured as a function of temperature with and without the laser beam shining onto the manganite bridge. The setup includes two lasers, a continous wave laser (Toptica Photonics, λ = 640nm) and a femtosecond laser (Femtolaser Fusion, λ ≈ 800nm). We observed a change of the first and third harmonic voltage close to the metal insulator transition under the influence of the laser light. For manganite systems the third harmonic voltage can be associated with the concentration of correlated polarons, hence the results are discussed in terms of a light induced change of the concentration of correlated polarons. Financial support by DFG via SFB 602, TPA2 and the Leibniz Program is acknowledged.