Preparation of Ca _0.8Sm _0.2MnO ₃ powders and effects of calcination temperature on structure and electrical property

The Ca _0.8Sm _0.2MnO ₃ (CSM) powders were prepared through sol-gel auto-combustion technology. The preparation temperature was determined by TG-DTA, FTIR, and XRD analyses, which indicated that the synthetic temperature of CSM powders was 900°C. Effects of calcination temperatures higher than 900°Con the structure and electrical property of CSM powders were also investigated. The crystallography data calculated from XRD spectra illustrated that the cell parameters which related to the resistivity of CSM powders were affected by calcination temperatures. SEM and EDAX analyses demonstrated that the higher calcination temperature led to the larger size of grains. The suitable crystallite size was helpful to decreasing the resistivity, and the CSM powders with the lowest resistivity of 0.2920Ω.m were obtained by calcining the powders at 1000°C.