Relaxor Pb(Mg1/3Nb2/3)O₃ thin films and their electromechanical properties

Pb(Mg⅓Nb⅔)O3 thin films were prepared from modified alkoxide solution precursors and their dielectric and electromechanical characteristics were investigated. Preparation of the films is very sensitive to processing parameters. The influence of different seeding layers on the microstructures is discussed. Films show relaxor-like behavior, but with dielectric permittivity which is low (4500 at peak) compared to bulk ceramics and single crystals. Large electric dc bias fields (up to 120 kV/cm) can be applied to the films. This dc field reduces the permittivity, suppresses the frequency dispersion and flattens the permittivity peak. No anomaly in temperature dependence of the permittivity associated with the field induced transition into a ferroelectric phase was observed. The maximum field induced piezoelectric d33 coefficient is around 85 pm/V and electrostrictive strains up to 1.6 10−3 were measured with an electric field of 30 kV/cm.