The most widely used piezoelectric ceramics are lead oxide
based ferroelectrics, especially Pb(Zr, Ti)O3 (PZT) due to
their high piezoelectric response close to a morphotropic
phase boundary (MPB) between rhombohedral and tetragonal
phases. However, conventional PZT ceramic materials
have serious depoling and ageing problems at temperature
above 200 1C that significantly limits their applications as
high-temperature actuators and/or sensors, such as oil-flow
control in automobile engines [1–3]. Therefore, researchers
worldwide are looking for alternative new materials that may
show higher working temperature.