Nonlinear optical response in a ferromagnetic insulating manganite: Pr$_{0.8}$Ca$_{0.2}$MnO$_{3}$

TL;DR

This study investigates high harmonic generation in Pr$_{0.8}$Ca$_{0.2}$MnO$_{3}$ across different magnetic phases, revealing a decrease in harmonic intensity in the ferromagnetic phase and proposing a phase transition-related explanation.

Contribution

It provides new insights into the nonlinear optical response of ferromagnetic insulating manganites across phase transitions.

Findings

Harmonic intensity increases with decreasing temperature in the paramagnetic phase.

Harmonic intensity decreases in the ferromagnetic phase.

Anomalies are linked to orbital order fluctuations and phase separation.

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.