Photoinduced phase transition in strained manganite films studied by ultrafast single-shot spectroscopy

Yu-Hsiang Cheng^1,2*, Keith A. Nelson³

¹Electrical Engineering, National Taiwan University, Taipei, Taiwan
²Electrical Engineering and Computer Science, Massachusetts Institute of Technology, MA, USA
³Chemistry, Massachusetts Institute of Technology, MA, USA

* Presenter:Yu-Hsiang Cheng, email:yuhsiang@ntu.edu.tw

We performed single-shot pump-probe measurement on strained La_2/3Ca_1/3MnO₃ thin films with near infrared and terahertz pulses. The film, an antiferromagnetic insulator, was turned into a ferromagnetic
metallic phase after excited by 800-nm laser pulses. We monitored the insulator-to-metal transition shot-by-shot with our single-shot spectroscopy. We found that once photogenerated, part of the metallic domains stayed persistently while other parts quickly returned to the insulating phase. The volume fraction of the persistent metallic phase grew with laser shots until coalescing into a metallic layer, whose thickness was determined by the photon density.

Keywords: Pump-probe spectroscopy, Single-shot spectroscopy, Photoinduced phase transition, Terahertz spectroscopy