Pyroelectric and Dielectric Properties of Mn Modified 0.82Bi(0.5)Na(0.5)TiO(3)-0.18Bi(0.5)K(0.5)TiO(3) Lead-Free Thick Films

MnO-doped 0.82Bi(0.5)Na(0.5)TiO(3)-0.18Bi(0.5)K(0.5)TiO(3)(NBT-KBT) thick films with thickness about 40 mu m have been prepared using screen printing on Pt electroded alumina substrates. The strong pyroelectric coefficient of 3.8 x 10(-4) C center dot(m(2)center dot degrees C)(-1) was observed in 1.0 mol% MnO-doped-thick films, and the calculated detectivity figure of merit as high as 1.1 x 10(-5) Pa-0.5, which can be comparable to that of the commonly used lead based materials. The enhancement of the pyroelectric performances is attributed to the reductions in dielectric constant and loss and the improvements in the pyroelectric coefficient, which can be ascribed to the Mn acts as a hard dopant in the NBT-KBT lattice, creating oxygen vacancies and pinning the residual domains.