Synthesis and Characterization of Nano Sized Pure and Doped Barium Titanate Powders Prepared by Sol Gel Emulsion Technique

Abstract

Barium titanate BaTiO3 due to its ferroelectric and electrical properties is used in a newlinevariety of applications such as multi layer ceramic capacitor MLCC sensors actuators newlinecurrent limiters PTCR thermistors constant temperature heaters dynamic random access newlinememories DRAMs etc Search for lead Pb free materials due to environmental newlineconcern led to further interest in the study of BaTiO3 owing to its simple crystal newlinestructure ability to accommodate various dopants and ease of being prepared in newlinepolycrystalline ceramic form Besides these the other advantages of BaTiO3 are higher newlinedielectric constant low dielectric loss and piezoelectric properties in the tetragonal phase newlineCurrent trend towards smaller size electronic components have gained momentum in newlinedeveloping BaTiO3 ceramics with an average grain size 100nm With reduction in size newlinethe structure and properties are known to deviate from those reported for the bulk This newlinephenomenon known as the size effect affects the dielectric properties and the crystal newlinestructure which is also sensitive to factors such as stoichiometry defects impurities newlineelectrical boundary conditions strain and stress Miniaturization of components to newlineachieve higher capacitance and reliability led to the demand for fabricating dense BaTiO3 newlinedielectric layers with uniform size nano grains Due to this the traditional soldstate newlinereaction synthesis route needed to be replaced with wet chemical routes such as solgel newlinehydrothermal coprecipitation etc since they offer relatively better compositional newlinecontrol and homogeneity Various dopants like Sr La Mg Ce Nb Pb Zr etc are added newlinein BaTiO3 to modify its properties by shifting the TC from its reported value increasing newlinedielectric constant broadening the temperature range of maximum dielectric constant newlineinducing PTCR effect etc In the present work nanosize BaTiO3 powders were synthesized via solgel emulsion newlinetechnique Waterinoil wo type emulsion used comprised of BaTiO3 sol as the water newlinephase and cyclohexane as the oil phase which was stabilized using span 80 and span 20.