Nonlinear optical response in a ferromagnetic insulating manganite: Pr${}_{0.8}$Ca${}_{0.2}$MnO${}_3$

Abstract

High harmonic generation from Pr${}_{0.8}$Ca${}_{0.2}$MnO${}_3$ was investigated across a high-temperature paramagnetic phase and a low-temperature ferromagnetic phase. As the temperature decreases, the harmonic intensity gradually increases in the paramagnetic phase like that in different composition material Pr${}_{0.6}$Ca${}_{0.4}$MnO${}_3$. However, it turns to a decrease in the ferromagnetic phase. We propose a possible interpretation of the anomaly around the ferromagnetic transition temperature considering the thermal fluctuation of orbital order and the metal-insulator phase separation in the ferromagnetic insulating phase.

10 pages, 5 figures