Chemical solution deposition (CSD) of BaTiO3 (BT) or BT-based thin films relies on using a carboxylic acid and alcohol as the solvents for alkaline-earth carboxylate and transition-metal alkoxide, respectively; however, the esterification reaction of the solvents may lead to in-situ water formation and precipitation. To avoid such an uncontrolled reaction, we developed a route in which ethylene glycol (EG) is used as the solvent for Ba-acetate. The EG-based BT coating solutions are stable for at least a few months. The thermal decomposition of the BT xerogel obtained by drying the EG-based solutions depends on the choice of the solvent for the Ti-alkoxide as well: in the case of EG and 2-methoxyethanol solvents carbon residues are removed at only about 1100 °C, while in the case of ethanol it is concluded at about 700 °C. About 100 nm thick BT films derived from the EG-ethanol solution deposited on platinized silicon reveal dense, crack-free columnar microstructure. They exhibit local ferro- and piezoelectric properties. The macroscopic polarization-electric field loops were obtained up to a quite high electric field of about 2.4 MV/cm. The EG-ethanol based CSD route is a viable alternative to the established acetic acid–alcohol route for BT and BT-based films.
The thermal treatment of electromechanically active thick films prepared by aerosol deposition (AD) is a common practice to improve their electrical and electromechanical properties. We report on how post-deposition annealing in air affects the unique cross-sectional microstructure and mechanical properties of 0.9Pb(Mg1/3Nb2/3)O3−0.1PbTiO3 thick films prepared by AD. Transmission electron microscopy revealed minor but detectable changes, such as pore redistribution and grain growth after annealing at 500 °C. We also showed that the stainless-steel substrate is strongly affected by the annealing. The hardness and Young’s modulus of the films increased after annealing, with both properties being discussed in terms of their distribution over the cross-sections of the films.
Ferroelectric materials are indispensable technological materials characterized by an intrinsic electric dipole that influences their structural and microstructural properties as well as their macroscopic functionalities. In recent years, despite their notorious brittleness, mechanical deformation has been employed to introduce dislocations into ferroelectric as structural defects in order to control their macroscopic properties [ 1, 2]. This approach has revealed a gap in the comprehension of the mechanical deformation of these materials and the interactions of dislocations with other structural features of ferroelectrics, such as domain walls, i.e. interfaces separating parts of the same direction of spontaneous polarization [ 3].