Photostrictive Characteristics of Fine-Grained PLZT Ceramics Derived from Mechanically Alloyed Powder

Lanthanum-modified lead zirconate titanate (PLZT) ceramics possess a photostrictive effect that is applicable to photo-driven and wireless actuators. The photostrictive strain is expressed in a product of piezoelectric constant and photovoltage, and it is theoretically explained that a grain size reduction enhances photovoltage. Dense PLZT ceramics with grain size of 0.16-1.84 μm were obtained by sintering a mechanically alloyed (MA) powder. As the grain size decreased, the photostrictive strain increased and exhibited its maximum value of ≈1×10-4, which is equivalent to electric-field-induced strain in common piezoelectric ceramics. This proved that a reduction of grain size is effective for the enhancement of photostrictive strain. Additionally, further improvement in photostrictive strain of the PLZT ceramics with fine grains could be predicted by performing a poling treatment at higher electric-fields.