Electronic Raman scattering and photoluminescence from La$_{0.7}$Sr$_{0.3}$MnO$_3$ exhibiting giant magnetoresistance

TL;DR

This study investigates the electronic excitations in La$_{0.7}$Sr$_{0.3}$MnO$_3$ using Raman and photoluminescence techniques, revealing plasmon and intersite electronic transitions that vary with temperature.

Contribution

It provides new insights into the electronic excitations and their temperature dependence in La$_{0.7}$Sr$_{0.3}$MnO$_3$, a material exhibiting giant magnetoresistance.

Findings

Raman mode at 1800 cm$^{-1}$ attributed to plasmon excitation

Photoluminescence band at 2.2 eV from intersite electronic transitions

Peak intensities decrease with increasing temperature

Abstract

Raman and Photoluminescence (PL) experiments on correlated metallic La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ have been carried out using different excitation wavelengths as a function of temperature from 15 K to 300 K. Our data suggest a Raman mode centered at 1800 cm$^{-1}$ and a PL band at 2.2 eV. The intensities of the two peaks decrease with increasing temperature. The Raman mode can be attributed to a plasmon excitation whose frequency and linewidths are consistent with the measured resistivities. The PL involves intersite electronic transitions of the manganese ions.