At present, the most widely used piezoelectric materials are
Pb(Zr, Ti)O3-based ceramics because of their superior piezoelectric
properties [1]. PZT with high dielectric and piezoelectric exists at
the morphotropic phase boundary (MPB) between rhombohedral
and tetragonal phases [2]. Therefore, MPB composition ceramics
for piezoelectric transducer, sensor and resonator have been
widely utilized due to their excellent piezoelectric effect [3–5].
However, devices made from these compounds pose some environmental
concerns. Many manufacturers are currently being constrained
to reduce and ultimately eliminate lead content in their
devices [6]. Moreover, upcoming environmental regulations in Europe,
parts of Asia, and US prohibit the use of lead-based materials
because of their toxicity. For this reason, alternative lead-free piezoelectric
systems analogous to PZT are urgently desired