Optical spectra measured on cleaved surfaces of double-exchange ferromagnet La1-xSrxMnO3

TL;DR

This study measures optical spectra of La1-xSrxMnO3 single crystals to understand their electronic properties, revealing an incoherent-to-coherent crossover and surface sensitivity in optical responses.

Contribution

First detailed optical spectra on cleaved La1-xSrxMnO3 surfaces showing the incoherent-to-coherent crossover and surface condition effects.

Findings

Incoherent-to-coherent crossover observed in optical conductivity.

Low-temperature ferromagnetic phase shows a pronounced Drude component.

Optical spectra are sensitive to sample surface conditions.

Abstract

Optical reflectivity spectra were measured on cleaved surfaces of La1-xSrxMnO3 single crystals (x=0.175, T_C=283 K) over a temperature range 10-295 K. The optical conductivity $sigma(\omega)$ shows, keeping single-component nature, incoherent-to-coherent crossover with increase of electrical conductivity. The $\sigma(\omega)$ spectrum of low-temperature ferromagnetic-metallic phase (10 K) exhibits a pronounced Drude-like component with large spectral weight, contrary to the previous result. The present result indicates that the optical spectrum of the manganites is sensitive to condition of sample surfaces.