Lead-free ceramics of composition Bi(Mg₁/₂Ti₁/₂)O₃-(Bi₁/₂K₁/₂)TiO₃-(Bi₁/₂Na₁/₂)TiO₃ were prepared
using solid state synthesis techniques. The dielectric spectra showed a Tmax of more than 320 °C
for all compositions, and the transitions became increasingly diffuse as the Bi(Mg₁/₂Ti₁/₂)O₃
content increased. A lower temperature transition, indicating a transformation from an ergodic to a
non-ergodic...
The piezoelectric fatigue behavior of Pb-free ceramics based on solid solutions of Bi(Zn₀.₅Ti₀.₅)O₃-(Bi₀.5K₀.₅)TiO₃-(Bi₀.₅Na₀.₅)TiO₃ was characterized at 50 kV/cm after 10⁶ bipolar cycles. Ferroelectric compositions containing 2.5% Bi(Zn₀.₅Ti₀.₅)O₃ exhibited only minor losses in maximum strain (~10%). In compositions with 5% Bi(Zn₀.₅Ti₀.₅)O₃ that exhibit large electric field-induced strains, the electromechanical strain actually...
Polycrystalline ferroelectric lead-free 85 mol% (Bi₀.₅Na₀.₅)TiO₃–10 mol% (Bi₀.₅K₀.₅)TiO₃–5 mol% BaTiO₃ (85BNT–10BKT–5BT) thin films were fabricated via chemical solution deposition on platinized silicon substrates. The permittivity and dielectric loss at 1 kHz were 610 and ∼3.5%, respectively. The ferroelectric properties at room temperature and as a function of the temperature up...
Solid solutions ceramics of the Bi(Zn0.5Ti0.5)O-3-(Bi0.5K0.5)TiO3-(Bi0.5Na0.5)TiO3 ternary system for <20 mol. % BZT were created and confirmed to be single phase using x-ray diffraction. The dielectric dispersion showed decreasing T-max of the dielectric spectrum with a broadening of the transition with increasing BZT content. At 2.5BZT-40BKT-57.5BNT, a secondary transition commonly...
Lead-free Bi(Mg₁/₂Ti₁/₂)O₃-(Bi₁/₂K₁/₂)TiO₃-(Bi₁/₂Na₁/₂)TiO₃ (BMT-BKT-BNT) ceramics have
been shown to exhibit large electromechanical strains under high electric fields along with
negligible fatigue under strong electric fields. To investigate the role of point defects on the
fatigue characteristics, the composition 5BMT-40BKT-55BNT was doped to incorporate acceptor and
donor defects on the A and...
In order to develop dielectric ceramics with temperature-stable permittivity characteristics, perovskite BaTiO[subscript 3]-Bi(Zn[subscript 1/2]Ti[subscript 1/2])O-[subscript 3]-NaNbO[subscript 3] ceramic solid solutions were investigated with a particular focus on effects of BaTiO[subscript 3] and NaNbO[subscript 3] contents on the dielectric properties of ternary compounds. Keeping the ratios of the other two constituents...
The dielectric spectra of CaCu₃Ti₄O₁₂ is characterized by a large permittivity (εᵣ>10 000) with only a weak dependence on temperature over the temperature range 200–400 K. In this work, doping with 0.1–1.0 wt % ZrO₂ has been shown to dramatically reduce the dielectric loss. At 0.5 wt % ZrO₂, tan...
The crystal structure and multiferroic properties of single-phase (Bi₀.₉La₀.₁)FeO₃–Ba(Fe₀.₅Nb₀.₅)O₃ ceramics were investigated. The rhombohedral-type structure of 1.0(Bi₀.₉La₀.₁)FeO₃) was transformed to a monoclinic-type structure for the 0.5(Bi₀.₉La₀.₁)FeO₃–0.5Ba(Fe₀.₅Nb₀.₅)O₃) composition. It shows the coexistence of ferroelectricity and magnetism at room temperature, represented by a high dielectric constant with ferroelectric hysteresis and clear magnetic...
The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO₃–0.2Bi(Zn₁/₂Ti₁/₂) O₃ were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti³⁺-related defect center, which is correlated with lower resistivities and an electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium vacancy-oxygen vacancy...
Materials based on BiMO₃-modified BaTiO₃ have been shown to exhibit a number of attractive electrical and electromechanical properties. In addition, many of the materials in this broad family exhibit reduced sintering temperatures for densification as compared to pure BaTiO₃. We report here a study of the phase evolution and sintering...