摘要
In this study,the double-layered Aurivillius phases CaBi_(2)Ta_(2)O_(9)(CBT)and PbBi_(2)Ta_(2)O_(9)(PBT)were prepared through a hydrother-mal route with NaOH as a mineralizer.XRD analysis confirmed that the CBT and PBT compounds were successfully formed and adopted an orthorhombic crystal structure with an A21am symmetry.Le Bail refinements of XRD data indicated that the unit cell volume of CBT was smaller than PBT and is associated with the smaller ionic radius of Ca^(2+)compared to Pb^(2+).The surface mor-phology of both samples,as determined using SEM,demonstrated plate-like grains with anisotropic grain growth.It was found that the different ionic radii of A-site cations(Ca^(2+)and Pb^(2+))strongly affected the structural,optical and electrical properties of the Aurivillius phase.The occupation of smaller Ca^(2+)cations induced a higher structural distortion,which resulted in higher bandgap(Eg)energy and ferroelectric transition temperature(Tc)of CBT,compared to those of PBT.
基金
This research was funded through PMDSU Scholarship Grant No.050/SP2H/LT/DRPM/2018 sponsored by the Ministry of Research,Technology and Higher Education(RISTEKDIKTI)of The Republic of Indonesia.
