Preparation and Pyroelectric Properties of (Pb, La)(Zr, Ti)O₃ (PLZT) Thin Films

PLZT films around 3 µ m thick with compositions of {(Pb 0.925 La 0.075 )(Zr y Ti 1- y ) 0.981 +0.5 mass% MnO 2 } where y =0–0.10, which have an appropriately small relative dielectric constant ( ∼200) were deposited on Pt(100)/ MgO(100) by rf-magnetron sputtering. The pyroelectric properties of PLZT films as element materials for pyroelectric IR sensors were investigated in detail. Assuming that the volume specific heat C v of the present films is 3.2 J/cm 3 · K, the PLZT films exhibited the highest F.M. of 1.4×10 -10 C· cm/J and F.M.D * of 1.6×10 -8 C· cm/J, which were around 1.8 times and 1.5 times larger than those of PLT films, respectively. Consequently, the figures of merit for the pyroelectric IR sensors could be improved by adding a small amount of Zr to PLT.