The effects of donor (Nb5+) and acceptor (Cu2+, Zn2+, Mn2+, Mg2+) doping at B-site on crystal structure, microstructure, and electrical properties of (Ba0.85Ca0.15)Zr0.1Ti0.9O3 ceramics

Abstract (Ba0.85Ca0.15)Zr0.1Ti0.9O3 (BCZT) ceramics with donor (Nb5+) and acceptor (Cu2+, Zn2+, Mn2+, Mg2+ ions) doping at B-site were fabricated in this study. The effects of crystal structure, microstructure, and chemical defects, on dielectric properties and piezoelectric coefficient (d33) of all samples, were observed. The addition of Mn2+ and Mg2+ ions could reduce the sintering temperature of BCZT from 1,450 oC to 1,300 oC; meanwhile, the others did not affect the microstructure of BCZT significantly. The ion substitution influenced the phase fraction, lattice parameters, and tetragonality of BCZT ceramic. The addition of Mg2+ ions decreased greatly Tm of BCZT from ~117 oC to ~76 oC. The addition of Nb5+, Cu2+, and Mn2+ shifted Tm of BCZT to higher temperature. The relationship between decrease of tetragonality and decrease of Tm was observed in these ceramics. The diffuse dielectric behavior of the doped BCZT was induced due to microscopic heterogeneity in the composition. The change in microstructure and the formation of chemical defects (A-site vacancies and oxygen vacancies) significantly affected the polling condition of BCZT ceramic. The crystal structure, microstructure, dielectric, and piezoelectric properties of BCZT ceramic could be modified using these dopants. The results here suggested that BCZT ceramics might become an alternative material for dielectric and piezoelectric devices.