Piezoelectric and ferroelectric ceramics with a high Curie temperature (Tc) have attracted much attention owing to their applications in severe environments. In this work, phase structure and dielectric, ferroelectric, and piezoelectric properties of (0.975 − x)BiScO3-xPbTiO3-0.025Pb(Cd1/3Nb2/3)O3 (BS-xPT-PCN) ceramics (x = 0.58–0.64) were studied. A composition-induced structural transformation occurs from the rhombohedral to tetragonal phase through an intermediate monoclinic phase with the increasing PT concentration. The relationship between the structure and electrical properties of the system was discussed. The BS-xPT-PCN system near the morphotropic phase boundary (MPB) (x = 0.62) exhibits excellent piezoelectric and ferroelectric performances with d33 = 508 pC/N, kp = 56%, and Pr = 40 μC/cm2. The high-temperature piezoelectricity of the sample with MPB (x = 0.62) was characterized by an in situ XRD. The excellent thermal stability of the crystal structure and the piezoelectric property indicate that the BS-xPT-PCN system is a promising candidate for high-temperature piezoelectric applications.

Highly (100) oriented lead strontium titanate (Pb 0.4 Sr 0.6 TiO 3 ) thin films were deposited on LaNiO 3 -coated Si substrate via radio-frequency magnetron sputtering method with substrate temperature ranging from 300 to 500°C. The PST thin films were crystallized at a temperature as low as 300°C, which may result from the well-controlled stoichiometry and the in situ crystallization on seed layer. At an electric field of 400 kV/cm, high tunability of 43% and 57% can be achieved for PST films deposited at 300°C and 500°C, respectively. Moreover, the dielectric response shows weak frequency dependence and the loss factor stays relatively low. The results suggest that such films should be promising candidate for the microwave tunable devices compatible with the current Si technology.

High‐performance colossal‐permittivity (CP) materials have huge potential applications in the miniaturization of electronic components and high‐energy storage applications. Here, we report CP behavior in rare‐earth Ln‐doped BaTiO3 (Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er) ceramics. CP (>1 × 105) and low loss (<5% at 1 kHz) were achieved. Additionally, all ceramic samples with excellent temperature stability over a wide temperature range (25–250°C). X‐ray photoelectron spectroscopy verified the existence of point defects (Ti3+ and VnormalO••$V_{\rm{O}}^{{\rm{ \bullet \bullet }}}$) in Ln‐doped BaTiO3 ceramic samples annealed in an N2 atmosphere. Electron paramagnetic resonance further demonstrated the existence of Ti3+. The coupling of point defects forms an electron‐pinned defect‐dipoles (EPDD) effect and induces strong hopping polarization. In addition, an internal barrier layer capacitance (IBLC) effect and a surface barrier layer capacitor (SBLC) effect are identified by impedance spectroscopy and DC bias voltage. The CP is attributed to the combined effect of EPDD, IBLC, and SBLC. Furthermore, the high‐temperature stability of CP is related to the strong coupling of defect‐dipole complexes.

Pb x Sr 1-x TiO 3 (PST) thin films with the ratio Pb/Sr = 40/60 were deposited on silicon substrate with Pt or LaNiO 3 (LNO) bottom electrodes by radio frequency magnetron sputtering followed by a postannealing treatment. The structural and microstructural analyses were performed and a perovskite phase was obtained whatever the nature of the bottom electrodes and even at a low temperature (450°C). The optimal annealing temperature is 650°C at which the films have a dense and fine microstructure. For electrical characterization the different top electrodes (Pt and LNO) were used. In both cases, we demonstrate that PST films present excellent performances in terms of dielectric properties and in particular, the tunability and Figure of Merit. A large tunability (57% at 400 kV/cm) and low dielectric losses (1.4%) were measured at 10 kHz for Pt/ PST/Pt structures postannealed at 500°C. For LNO/PST/ LNO structures, postannealed at 650°C, the improved tunability (%80%) and low loss factor (%2%) were obtained. Prospects of PST as an alternative to BST for tunable applications with a real potentiality of monolithic integration with silicon, in terms of thermal budget, are considered.