Relaxor Pb(Mg1/3Nb2/3)O3 thin films:: Processing, dielectric and electrostrictive properties

Lead magnesium niobate, Pb(Mg1/3Nb2/3)O-3, thin films were formed from alkoxide-based solution precursors. To obtain stable and reproducible PMN precursor solution, a special effort has been undertaken to optimize the precursor synthesis. The organic decomposition behavior and crystalline phase development in a dried gel powder are reported. The influence of different seeding layers on the microstructures is shown. Dielectric and electromechanical measurements were carried our. Films show relaxer-like behavior, but with dielectric permittivity which is low (4500 at peak) compared to bulk ceramics and single crystals. Several parameters which might be responsible for this lower permittivity are suggested. Large electric de bias fields (up to 120 kV/cm) can be applied to the films. This de field reduces the permittivity, suppresses the frequency dispersion and flattens the permittivity peak. The anomaly associated with the field induced transition into a ferroelectric phase was not observed. Electrostrictive strains versus amplitude of electric field were measured and are discussed.