Emissivity and Optical Properties of Thermochromic Material LaCaSrMnO (0 ≤ x ≤ 0.3).

LaCaSrMnO (0 ≤ x ≤ 0.3) (LCSMO) is a thermochromic material. The material can show a phase transition from ferromagnetic-metal to paramagnetic-insulator under the appropriate doping level ( x). In this paper, LCSMO compounds were synthesized by a conventional solid-state reaction method. The normal emissivity and the spectral reflectance of LCSMO with different doping levels ( x) are experimentally investigated. Based on the spectral reflectance data, the optical constants (refractive index n and extinction coefficient k) are calculated by using Kramers-Kronig (K-K) relations. Then, the emissivity changing mechanism is discussed. The experimental results show that the emissivity of LCSMO increases with increasing temperature. For the samples with x = 0.1 and 0.15, their emissivity has a sudden change in the vicinity of the phase transition temperature T. [ABSTRACT FROM AUTHOR]