Thermally assisted electro-active regions in SrMnO3 ceramics

Conditions were optimized to prepare SrMnO3 via sol-gel auto-combustion route, by varying calcination temperature from 600 to 1200 degrees C. Single phase synthesis was confirmed by X-ray diffraction in the sample calcined at 1000 degrees C for 4 h. Rietveld's refinement was performed to obtain the detailed information regarding the structural parameters of the manganite sample. The effect of calcination temperature on dielectric, and impedance studies has been reported from a low (20 Hz) to a high frequency region (20 MHz) SrMnO3 ceramic samples. The dielectric response reveals electroactive regions in accordance with the Maxwell-Wagner model while the impedance analysis shows the dominant behaviour of microstructural grain boundaries. The resistive parameters were then optimized to calculate the grain/grain boundary capacitance. A possible combination of equivalent circuit is also fitted in order to determine the deviation from idealistic behaviour in impedance analysis. These circuits are also verified through frequency dependent conductivity response while the dependence of capacitance on temperature gives the information on the possible ferroelectric behaviour. (C) 2017 Elsevier B.V. All rights reserved.