Preparation and Pyroelectric Properties of Mn-Modified (Pb, La)(Zr, Ti)O3 (PLZT) Ceramics

High density lanthanum-modified lead zirconate titanate (PLZT) ceramics with compositions of { (Pb0.925La0.075)(Zr y Ti1- y )0.981O3+0.5 mass% MnO2}, where y=0.1–0.9, were prepared by hot iso-static pressing (HIP). After the relative dielectric constant ε r at room temperature increased gradually with increasing Zr content in the tetragonal region, exhibiting a maximum in the vicinity of the morphotropic phase boundary (MPB) between tetragonal and rhombohedral structures, it decreased remarkably in the rhombohedral region. For 0.2≦y≦0.5, the pyroelectric coefficient P at room temperature showed relatively large values (≧3.0×10-4 C/m2· K). The PLZT sample for y=0.2 exhibited the highest figures of merit (F.M.) for voltage responsivity R v of approximately 3.0×10-13 C· m/J and ( F.M.D*) for specific detectivity D * of approximately 10.5×10-11 C· m/J among the seven samples studied.