Nonlinear-optical properties of thin La0.7Ca0.3Mn O3 films and dynamics of photoinduced phase transition

Abstract

Strong optical second-harmonic was observed in a centrosymmetric LCMO thin films in ferromagnetic phase and assigned a s magnetization-induced effect. B y n on-linearopticalexperiment, magnetization is shown to be sensitivefor laser illumination. A threshold of photoinduced demagnetisation depends on the films structure: it isdrastically decreases in the presence of grain boundaries. For steady state conditions, the SHG field is described bypower law with critical exponent 2β=0.64±0.05. Abovethe threshold a complicated dynamics of photoinduceddemagnetization is observed, which is modeled byphotoinduced modification of electron phase separation.