Radiative and optical properties of polycrystalline La1-xSrxMnO3 (0≤ x ≤ 0.4) in the vicinity of the metal-insulator transition are presented. The temperature dependence of the total hemispherical emittance εH of La1-xSrxMnO3 was measured by the calorimetric method in the temperature range from 173 to 413 K. It was confirmed that εH showed unexpected variation as a result of changes in the hole concentration (x). Especially in the case of La0.825Sr0.175MnO3, εH remains high above the transition temperature TC due to insulator-like behavior; on the other hand, it decreases sharply below TC because of metallic behavior. The spectral reflectance was measured by FT-IR in the wavelength range of 0.25 to 100 μm at room temperature. The optical constants were calculated by Kramers-Kronig analysis of the spectral reflectance data. An insulator-like character of the optical properties appears at lower Sr2+ doping levels while a metallic one exists at higher Sr2+ doping levels.
ASJC Scopus subject areas
- Condensed Matter Physics