Structure and electrical properties of (111)-oriented Pb(Mg1/3Nb2/3)O3??PbZrO3??PbTiO3 thin film for ultra-high-frequency transducer applications

Ternary lead magnesium niobate-lead zirconate titanate system 0.4Pb(Mg_1/3Nb_2/3)O₃-0.25PbZrO₃ 0.35PbTiO₃ (40PMN-25PZ-35PT) thin film with a thickness of 1.5 μm was grown on Pt(111)/Ti/SiO₂/Si substrate via chemical solution deposition. X-ray diffraction and transmission electron microscopy results suggested the film obtained was highly (111)-oriented. The remanent polarization and coercive electric field of the film were found to be 25.5 μC/cm² and 51 kV/cm, respectively. In addition, at 1 kHz, the dielectric constant was measured to be 1960 and the dielectric loss 0.036. The film was observed to undergo a diffuse ferroelectricto-paraelectric phase transition at around 209°C. The leakage current appeared to depend on the voltage polarity. If the Au electrode was biased positively, the leakage current was dominated by the Schottky emission mechanism. When the Pt electrode was biased positively, the conduction current curve showed an ohmic behavior at a low electric field and space-charge-limited current characteristics at a high electric field.