Effect of external pressure and grain size on the phase transition in the Gd-doped BaTiO3 ceramic

Phase transition in barium titanate nanocrystals by chemical treatment

“…There has been considerable interest in developing new processes for BaTiO 3 powders synthesis allowing the formation of submicrometer homogeneous tetragonal phase particles. 2 The phase transition of BT occurs at three temperatures in the vicinities of −90, 5 and 130 • C. 3,4 Above 130 • C BT has a stable cubic phase. In the temperature range of 5 and 130 • C, the crystal is spontaneously polarized along a 1 0 0 direction, accompanied with tetragonal symmetry.…”

Particle size effect on the microstructure and the aging process of flash-sintered barium titanate from micro and nanopowders

“…S19, ESI †), which can be explained in terms of a higher concentration of oxygen vacancies 37 or lattice stress relaxation. 38,39 The evolution of the impedance given in Fig. 2 and the corresponding activation energy shift towards lower values reported in both Fig.…”

“…S19, ESI†), which can be explained in terms of a higher concentration of oxygen vacancies 37 or lattice stress relaxation. 38,39…”

“…S21 (ESI †): after treating a fresh sample for a week at 900 1C, both tetragonal-orthorhombic and orthorhombic-rhombohedral transitions shift towards a lower temperature, and the intrinsic dielectric response increases, suggesting a change in both the lattice parameter and the unit cell structure. 39 When the heat-treated sample is then held in vacuum for a week, it forms oxygen vacancies, and its intrinsic dielectric response shifts back to a lower value. After the lattice is reoxidized, the sample becomes relaxed and evolves spontaneously, annihilating the oxygen vacancies slowly over time.…”

Grain-Oriented Bi0.5Na0.5TiO3–BaZrO3 Piezoelectric Ceramics

“…Numerous research efforts have been devoted to the candidate lead-free piezoelectric materials such as BaTiO 3 (BT), K 0.5 Na 0.5 NbO 3 (KNN), and Bi 0.5 Na 0.5 TiO 3 (BNT) because of their interesting electromechanical properties. The BT-based ceramics are interesting from the view point of their good ferroelectricity, chemical, and mechanical stability along with easy processing in polycrystalline form [9,10]; however, they are inadequate for device applications due to their low Curie temperature (T c ≈ 120°C) [11,12]. Alternatively, The KNbO 3 -NaNbO 3 solid solution or the (K,Na)NbO 3 (KNN)-based material exhibits good piezoelectric properties as well as high T c ≈ 420°C and have been studied as substitutes for PZT-based ceramics [13][14][15][16].…”