Effect of MnO addition on structure and electrical properties of (Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics prepared by citrate method

(Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics added with 0–0.8 wt.% MnO were prepared by a citrate method, and the influence of the MnO addition on the structure and electrical properties was investigated. The results indicate that the addition of small amounts of MnO did not cause a remarkable change in crystal structure, but resulted in an evident evolution in microstructure. The dielectric constant (ɛr) and piezoelectric constant (d33) significantly decrease with increasing MnO content, while the electromechanical coupling factor (kp) presents a slight variation in the range of 0.25–0.28. The dissipation factor (tan δ) and mechanical quality factor (Qm) attain a minimum value of 1.5% and a maximum value of 304 when adding 0.4 and 0.5 wt.% MnO, respectively. This research demonstrates that doping effect and microstructural evolution contribute cooperatively to the electrical properties of the ceramics.