Strontium-modified lead zirconate titanate thin films for electrically tunable device applications

摘要

Strontium-modified lead zirconate titanate Pb_(1-x)Sr_xZr_(0.52)Ti_(0.48)O_3 [(PSZT) x=0.2-0.8] thin films were prepared on Pt/TiO_2/SiO_2/Si substrates by the sol-gel method. The Curie temperature of PSZT films decreases with the increase of Sr contents and paraelectric PSZT films at room temperature are demonstrated as x approaches 0.4. The increase of Sr contents also leads to the simultaneous decrease of dielectric constant, tunability, and dielectric loss. The composition dependence of Curie temperature and tunability can be attributed to the shrinkage of crystal lattice due to a Sr addition. PSZT films with x=0.6 show the largest figure of merit of 24 with a moderate tunability of 48% and a dielectric loss of 0.02. This suggests that Sr-modified PZT is a potential candidate for voltage tunable applications.