Ultrafast detection of coherent wrinkling on a freestanding functional oxide thin film*

Complex oxides have long been known as hosts for many fascinating phenomena such as superconductivity and colossal magnetoresistance. Recently, the successful synthesis of freestanding thin films of complex oxides opened up new ways of probing and controling these materials. In this work, by using ultrafast electron diffraction (UED), we reconstruct the real-space wrinkling dynamics due to a photoinduced coherent acoustic phonon in La2/3Ca1/3MnO3 freestanding thin films. From the wrinkling in the freestanding thin film, we further extract information on thin film morphology as well as strain properties with picosecond time resolution.