The effect of B site doping on infrared emissivity of lanthanum manganites La0.8Sr0.2Mn1-xBxO3 (B = Ti or Cu)

The lanthanum manganites La0.8Sr0.2Mn1-xBxO3 (B=Ti or Cu, 0 <= x <= 0.4) were prepared by standard solid-state reaction method. The structure, infrared absorption, electron spin resonance (ESR) and infrared normal emissivity (epsilon(N)) in the 8-14 mu m waveband of the samples were systematically investigated. The samples are perovskite with distorted rhombohedral structure. Compared to x=0 sample with epsilon(N) value 0.693, infrared absorption occurred in the 8-14 mu m waveband leads to high emissivity value of the B site doping samples (epsilon(Ti) = 0.912 and epsilon(Cu)=0.894), and the epsilon(N) decreases slightly with increasing doping level due to decreasing transition probability indicated by ESR results. The EN changes slightly in the temperature range 293-373 K, from 0.9 to 0.882 for Ti doping and from 0.886 to 0.879 for Cu doping, owing to the weakening of the double-exchange interaction between Mn3+ and Mn4+. (C) 2010 Elsevier B.V. All rights reserved.