Investigation of Structural and Diffuse Phase Transition of New Nano Lead-Free System xBAO – yBZT − (1 − x − y) BCT

We present in this article the latest development of single-phase nanocrystalline ceramics, x (BiAlO 3 ) − y (BaZr 0.2 Ti 0.8 O 3 ) − (1 − x − y ) (Ba 0.7 Ca 0.3 TiO 3 ), abbreviated as x BAO − y BZT − (1 − x − y ) BCT with ( x , y ) = (0, 0.50), (0.01, 0.49), (0.03, 0.47), and (0.1, 0.4), which were prepared using a high-energy ball milling technique. In the current study, BZT − x BCT has been selected as a host system to be incorporated into BiAlO 3 . Their properties of structure, relative dielectric permittivity ( ε ), diffuse phase transition ( γ ), peak broadening ( δ γ ), and deviation from Curie–Weiss law (Δ T C ) were systematically investigated. However, the decreasing trend of Curie temperature ( T c ) in the system does not obey the Vegard’s law. Analysis of X-ray diffraction patterns shows the solid solubility of (Bi 3+ , Ca 2+ ) into A-site and that of (Zr 4+ , Al 3+ ) into B-site of pure BaTiO 3 lattice of tetragonal symmetry with space group P4mm. The values of γ (1.75 to 1.63) confirmed that the ceramic has intermediate behavior between the relaxor and normal ferroelectric, which is evaluated by modified Curie–Weiss law. The high value of quality factor (115), when x = 0.01, y = 0.49 at 1-kHz frequency and temperature 323 K (50 °C), decreases with the increasing frequency.