Role of O 2p-Ti 3d orbital hybridization in dielectric and ferroelectric properties of barium zirconate titanate ceramics

Barium zirconate titanate (BaZryTi1-yO3) ceramics for y = 0.10, 0.15 and 0.20 were synthesized using conventional solid-state method to study the effect of O 2p-Ti 3d orbital hybridization on dielectric and ferroelectric properties. X-ray diffraction, transmission electron microscopy and Rietveld refinement show structural phase transition from tetragonal P4mm to cubic Pm (3) over barm with increasing Zr concentration. Dielectric permittivity and Raman spectra show enhanced relaxor behavior which is attributed to decreased O 2p-Ti 3d orbital hybridization as Zr doping increased. Lattice distortion due to decreased O 2p-Ti 3d orbital hybridization induced by Zr doping caused lattice strain mismatch contributing to enhancement of dielectric permittivity. Reduced ferroelectric instability due to decreased Ti-O covalency with increasing Zr significantly reduced P-r values. Temperature dependent P-E loops shows increased W-rec and eta implying no energy dissipation and good thermal stability of BZT perovskites even at elevated temperatures which is beneficial for energy storage applications.