Synthesis and characterization of possible sustainable relaxor material Cax(Li0.5Bi0.5)1-x(Fe0.5Nb0.5)O3

Abstract

The role of Calcium (Ca) doping with Lithium (Li) in Bismuth (Bi)-site and Niobium (Nb) in Ferrite (Fe)-site on the electrical and magnetic properties of BiFeO3 ceramic has been investigated in this research. The Cax(Li0.5Bi0.5)1-x(Fe0.5Nb0.5)O3 ceramics with x = 0.00, 0.05, 0.10, 0.15 and 0.20 were synthesized by the conventional solid state reaction method. Dried solid solutions were calcined at 800 oC for 5 hours and then disk- and toroid-shaped samples were prepared and sintered at various sintering temperatures, e.g. 950, 975, 1000 and 1025 oC for 5 hours. Phase analysis by X-ray diffraction (XRD) indicates the formation of ―mixed crystal structure‖. Monte-Carlo and Grid Search simulation methods also run simultaneously with McMaill software for plane identification, which also indicate ―mixed crystal structure‖. Microstructural investigation using the Field Emission Scanning Electron Microscope showed that addition of Ca reduces the average grain size. Bandpass filter in frequency domain was used as digital image processing technique to observe grain boundary segregation. Permeability decreases with the increase of Ca content, as Ca itself is diamagnetic and so, less residual magnetism is also observed in M-H loop. But maximum permittivity observed x = 0.15 Ca for the samples sintered at 1000 oC.