High-density lead ferroniobate PbFe1/2Nb1/2O3 (PFN) is prepared by conventional ceramic technology. Its structural properties are studied in a wide temperature range (293 ≤ T≤ 973 K). The following...

The structure, lattice dynamics, and dielectric characteristics of Sr0.61Ba0.39Nb2O6(SBN-61) single crystals and SBN-61/(001)MgO thin films have been studied. The analysis of temperature...

Barium strontium niobate films ~300 nm in thickness have been grown on MgO(001) substrates by rf sputtering of a ceramic target with the stoichiometric composition Sr_0.5Ba_0.5Nb₂O₆ (SBN50) in an oxygen atmosphere. Composition–depth profiles across the films have been measured using secondary ion mass spectrometry, and we have determined their phase composition, structure, and c cell parameter in the temperature range 20–500°C. The results demonstrate that the SBN50 films are heteroepitaxial and have two crystallographic orientations with an angle of ~36.8° between them and identical tetragonal cell parameters (а = 12.438 Å and с = 3.955 Å). Their chemical composition does not vary in the thickness direction and corresponds to the composition of the ceramic target. The SBN50 films have a higher temperature of the ferroelectric-to-paraelectric phase transition than do SBN50 single crystals and polycrystalline films, and their thermal expansion coefficient changes sign near 100°C.

Thin films of congruent composition of the system of solid solutions of barium-strontium niobates Sr_0.61Ba_0.39Nb₂O₆ (SBN:61) with thicknesses from 30 to 630 nm on a MgO(001) substrate are deposited by RF-cathode sputtering in an oxygen atmosphere. According to the data of X-ray diffraction analysis, it is found that the films are free of impurity and monocrystalline. The deformations of the unit cells in the conjugation plane are practically absent in the films, and the tensile deformations are observed in the direction normal to the surface, which increase with decreasing film thickness. Dielectric measurements indicate high controllability in films.

The granular structure and the dielectric characteristics of the ceramic (Ba_0.5Sr_0.5)Nb₂O₆ solid solution are studied. The ceramic is found to be characterized by a homogeneous, dense, almost pore-free microstructure consisting of crystallites 5–10 µm in size. At room temperature, (Ba_0.5Sr_0.5)Nb₂O₆ exhibits elongated hysteresis loops. The ceramic undergoes a diffuse phase transition from a paraelectric state into the state of relaxor ferroelectric in the temperature range T = 340–385 K upon cooling. Scaling is shown to weakly change the ceramic characteristics of the material.