Critical fluctuations upon photoinduced phase transition in manganite strips

Abstract

Light, acting as an external stimulus to induce various intriguing phenomena ranging from photovoltaics to photoinduced catalysis, exerts prominent effects in strongly correlated systems. It would be of particular interest to investigate photon-induced emerging phenomena in spatially confined strongly correlated systems, which are important for applications of these materials in future electronic devices. Colossal magnetoresistive manganites materials offer an ideal platform for such study due to their sensitivity to photo-excitation. Here, we fabricated 900 nm wide La0.325Pr0.3Ca0.375MnO3 strips, whose width is comparable to the size of the electronic phase separation (EPS) domains in this system. We observed the photoinduced critical fluctuations in the strips, where abrupt resistivity jumps occurred upon photoinduced phase transition depending sensitively on the light intensity. Based on the microscopic views of the EPS domains under photoexcitation, we conclude that such photo-induced resistivity fluctuations originate from the photoinduced phase fluctuations of individual EPS domains when their size becomes comparable to the strip width.