Piezoelectric properties of Mn-doped (Na0.5Bi0.5)0.92Ba0.08TiO3 ceramics

Abstract Piezoelectric ceramics (Na 0.5 Bi 0.5 ) 0.92 Ba 0.08 TiO 3 + x mol.% Mn (BNBT-Mn) with x ranging from 0 to 2.97 are synthesized by conventional solid state reaction. The sintered BNBT-Mn exhibited a single phase perovskite structure without detectable secondary phase from x =0 to x =2.6. With increasing amount of doped Mn, the Curie temperature ( T c ) of BNBT-Mn decreased rapidly, piezoelectric constants d 33 and k t increased promptly when x was lower than 0.56, taking the maximum value of 160×(10 −12 C/N) and 58.5%, respectively for x =0.56, then decreased slightly with x ranging from 0.56 to 2.6, and finally decreased rapidly for x >2.6, whereas Q m showed a different trend from d 33 and k t . Furthermore, k t had a relatively high value under the low poling field ( E p ) for x =0.56 owing to the reduced coercive field ( E c ). Possible mechanisms of the influence of Mn doping on the microstructure and piezoelectric properties are discussed.