Influence of rare-earth addition on dielectric properties and relaxor behavior of barium zirconium titanate thin films

Ba(1-3/2x)MxZr0.20Ti0.80O3 (M=La, Ce, and Dy; x=0, 0.005, 0.01, 0.02, and 0.05) thin films are successfully deposited on Pt(111)/Ti/SiO2/Si(100) substrates by the sol-gel method, and the influence of the rare-earth ions content on the microstructure, dielectric properties, and phase transformation behavior is investigated in detail. As a result, the rare-earth ions with various ionic radii enter the perovskite lattice to substitute for A-site Ba2+ ions and inhibit the grain growth. With the increase in rare-earth ions concentration, the dielectric constant, dielectric loss, tunability, and leakage current density of Ba(1-3/2x)MxZr0.20Ti0.80O3 thin films decreased. Simultaneously the temperature of maximum of dielectric constant shifts to the lower temperature and relaxor phase transition behavior is observed due to the rare-earth ions substitution. And the degree of the relaxor behavior is enhanced with the increase in rare-earth ions content and ionic radius.