Phase transition and ferroelectric properties study of lead-free bulk 0.95BaTiO3-0.05CaSnO3 ceramics synthesized by high energy ball milling method

Abstract

There has been extensive research on Pb(Zr,Ti)O3 based material due to its excellent ferroelectric properties. However, the high content of toxic lead in PZT-based ceramics has raised environmental and health concerns and research trend in lead-free piezoelectric materials has attained considerable attention. Many BaTiO3-based lead-free materials like: (Ba,Ca)(Zr,Ti)O3, (Ba,Ca)(Sn,Ti)O3, and (Ba,Ca)(Hf,Ti)O3 with excellent piezoelectric properties have been discovered but (Ba,Ca)(Sn,Ti)O3 material is relatively less-studied. In the present work, 0.95BaTiO3-0.05CaSnO3 ceramics were synthesized by high energy ball milling (HEBM) assisted solid state reaction route. Calcination temperature and time for single phase formation was optimized to be 1100°C for 3 hr, which are considerably less than previous reports. X-ray diffraction (XRD) and Raman study were performed for phase examination of the synthesized material. Rietveld analysis confirmed the multiphase co-existance of this 95/05 system at room temperature. Sintering temperature and time for better densification were optimized to be 1250°C for 3hr. Substitution of Ca2+ and Sn4+ ions at Ba2+ and Ti4+ sites modified the phase boundary of pure BaTiO3 system. From dielectric study it was found that the whole effect of doping shifted the lower transition temperatures (R-O and O-T) to higher temperature side and reduced the higher ferroelectric-paraelectric phase transition (Tc) temperature towards lower temperature side. Polarization vs. electric field hysteresis loop study showed the development of saturated hysteresis loops but the remnant polarization was found decreased compared to pure BaTiO3 system.