Temperature dependence of infrared emissivity of doped manganese oxides in different wavebands (3–5 and 8–14 μm)

• Published in: Journal of alloys and compounds 2009-06, Vol.479 (1), p.420-422
• Main Authors: Shen, Xingmei, Xu, Guoyue, Shao, Chunming, Cheng, Chuanwei
• Format: Article
• Language: English
• Subjects: Ceramics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Infrared and raman spectra and scattering; Light absorption and reflection; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other nonmetallic inorganics; Physics; Solid-state reaction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.12.090

The manganese oxides La 1− x A x MnO 3 (A = Sr and Ca, x = 0.1–0.5) were prepared by standard solid-state reaction method. The structure, infrared absorption spectra and temperature dependence of infrared normal emissivity ( ɛ N) of the compounds in the 3–5 and 8–14 μm wavebands were systematically investigated. The XRD results indicate that Ca-doped samples are cubic, and Sr-doped samples are distorted rhombohedral. New infrared absorption occurs at 548 cm −1 for La 0.5Sr 0.5MnO 3 sample due to crystal distortion. In the 8–14 μm waveband, the ɛ N of Sr-doped samples increases with increasing temperature, while that of Ca-doped samples decreases due to insulator-like state. For La 0.8Sr 0.2MnO 3 sample, the ɛ N increases significantly in the temperature range 293–328 K, from 0.693 to 0.818, due to the metal–insulator phase transition. In the 3–5 μm waveband, the ɛ N of all the Sr-doped samples increases gradually with increasing temperature and no drastic change occurs, while that of Ca-doped samples remains constant in the whole temperature range.