Enhanced electrical properties in donor–acceptor co-doped Ba(Ti0.92Sn0.08)O3 ceramics

Abstract

In this work, lead-free piezoelectric ceramics Ba0.99Li0.005Al0.005(Ti0.92Sn0.08)O3-0.5%MnO2(BLATS-M) and Ba0.99Li0.005Nb0.005(Ti0.92Sn0.08)O3-0.5%MnO2(BLNTS-M) were synthesized by a solid-state reaction process. The influence of Li+–Al3+, Li+–Nb5+ ionic pairs on the microstructure, phase structure and electrical properties of Ba(Ti0.92Sn0.08)O3-0.5%MnO2(BTS-M) was systematically investigated. An orthorhombic (O) phase structure is obtained in all ceramics at room temperature. Both Li+–Al3+ and Li+–Nb5+ ionic pairs co-doping can enhance the piezoelectricity of BTS-M ceramic, while the Li+–Nb5+ doped BLNTS-M ceramic exhibits an optimum electrical properties: the piezoelectricity coefficient (d33) = 805 pC/N, the electromechanical coupling coefficient (kp) = 0.519, the relative permititivity (er) = 31900, the converse piezoelectric coefficient $$\left( {d_{{33}}^{*}} \right)$$ = 536 pm/V and the in situ quasi-static d33 with maximum $$\left( {d_{{33}}^{{\hbox{max} }}} \right)$$ = 1620 pC/N. The dielectric properties versus DC bias electric field experiments exhibit high dielectric tunability (ƞr = 97.78%) and figure of merit (FOM = 20.96) at 100 Hz and room temperature in BLNTS-M ceramic. The results suggest an effective approach to design high-performance piezoelectrics and dielectrics by appropriately selecting the types of donor–acceptor ionic pairs.