Sol-gel synthesis, characterization and microwave absorbing properties of nano sized spherical particles of La0.8Sr0.2Mn0.8Fe0.2O3

LSMFO (La0.8Sr0.2Mn0.8Fe0.2O3) nano sized powders were synthesized by modified EDTA assisted sol-gel synthesis using EDTA:metal ion = 0.5. Another new synthesis method, sol-gel self combustion using PVA, was also devised for the synthesis of LSMFO and the effects of the PVA mole ratio was investigated. The characterization techniques, XRD, FE-SEM, TG/DTA and ICP, confirmed the formation of the pure phase LSMFO by both the methods. The material attained spherical morphology instead of previously reported rod like structure. Sizes of synthesized powders vary from 14.5 nm to 23 nm. TG/DTA results suggest that LSMFO can be synthesized by the self combustion at temperatures as low as 200 degrees C. Synthesized LSMFO has excellent microwave absorbing properties in the range of 0.05-18 GHz and appreciable effective bandwidth, 2 GHz, with microwave absorption in excess of 10 dB and peak reflection loss of 25 dB which suggests that the materials can be used as effective microwave absorbers. (C) 2012 Elsevier Ltd. All rights reserved.