Microstructure and enhanced electrical properties of lead-free Bi1/2Na1/2TiO3–BaTiO3–La2CoMnO6 ternary system ceramics.

The structure, field-induced strain, polarization and dielectric response of lead-free La 2 CoMnO 6 -modified 0.935Bi 1/2 Na 1/2 TiO 3 –0.065BaTiO 3 (BNT–BT6.5– x LCMO, with x =0–0.020) ceramics were investigated. X-ray diffraction (XRD) patterns show that all compositions have a pure perovskite structure and LCMO effectively diffused into the BNT–BT6.5 lattice during sintering to form a solid solution. Around critical composition ( x =0.005) at a driving field of 70 kV/cm, large unipolar strain of 0.22% ( S max / E max =328 pm/V) and high piezoelectric constant of 211 pC/N are obtained at room temperature. The coercive field ( E c =18.6 kV/cm) drop down greatly, whereas the remnant polarization ( P r =28.8 μC/cm 2 ) decreases only a little at this critical composition. These results indicate that BNT–BT6.5– x LCMO ceramics can be considered as promising candidate materials for lead-free piezoelectric practical applications. [ABSTRACT FROM AUTHOR]