Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 40: Poster Session Correlated Electrons

TT 40.26: Poster

Wednesday, March 13, 2013, 15:00–19:00, Poster D

Pulsed Laser Induced Charge Carrier Excitation in Pr_0,65Ca_0,35MnO₃ — •Nils Folchert, Stephanie Raabe, and Christian Jooß — Institut für Materialphysik, Göttingen

Quite similar to electric and magnetic fields, optical stimulation of manganites like Pr_1−xCa_xMnO₃ (PCMO) can induce transitions from insulating to metallic conductivity. Applying a bias smaller than the threshold voltage of the electrically induced colossal resistance effect (CER), a short laser pulse can melt the charge-ordered state of PCMO yielding to-metal like conductive paths in the illuminated region. This state is preserved until the bias is switched off [1]. PCMO reveals strong correlation effects, i.e., strong electron-electron, electron-phonon and magnetic interactions. The change of these correlations during excitation is a still not very well understood phenomena of perovskite manganites. In order to investigate the transition, we performed time-resolved dc-measurements after pulsed laser excitations with frequencies varying from UV to Thz and at temperatures between 80 K to 300 K. The PCMO samples with x=0.35 were prepared by means of ion-beam-sputtering using single-crystalline MgO substrates. In this poster, we will mainly focus on the relaxation dynamics of the optically excited charge carriers.
[1] M. Fiebig et al., Appl. Phys. Lett. 74, 2310 (1999)