Repolarization of Ferroelectric Superlattices BaZrO/BaTiO.

With the use of the modified Sawyer-Tower scheme and Merz technique, studies were conducted on the repolarization characteristics of ferroelectric (BaZrO/BaTiO) superlattices on monocrystalline MgO substrate. Studies of temperature changes in the dielectric hysteresis loops indicated a sufficiently smooth decrease in spontaneous polarization compared with homogeneous barium titanate near the phase transition temperature of the superlattice. Experimental studies of switched currents have shown that the switching processes in the synthesized superlattices are implemented in two stages: activation motion ("creep" mode) and non-activation motion (slip mode).

Dielectric Properties and Switching Processes of Barium Titanate⁻Barium Zirconate Ferroelectric Superlattices.

This article is devoted to the investigation of the dielectric and repolarization properties of barium zirconate and barium titanate BaZrO₃/BaTiO₃ superlattices with a period of 13.322 nm on a monocrystal magnesium oxide (MgO) substrate. Synthesized superlattices demonstrated a ferroelectric phase transition at a temperature of approximately 393 °C, which is far higher than the Curie temperature of BaTiO₃ thin films and bulk samples.

Influence of Depolarizing Fields and Screening Effects on Phase Transitions in Ferroelectric Composites.

The temperature of the transition to the polar state in ferroelectric composites, representing spherical ferroelectric inclusions embedded in a dielectric matrix, under a depolarizing field effect is investigated. This temperature is determined both in the absence and presence of screening effects of the depolarizing field of the bound charges of spontaneous polarization at the inclusions surface. The absence case shows that the Curie point shift is determined by the ratio of the Curie constant of the ferroelectric inclusion to the permittivity of the matrix.

[Morpho-functional peculiarities of autoimmune gastritis in different age groups].

In 98 patients with chronic gastritis clinical-morphologic analysis was performed. The analysis included: the examination of gastric biopsy specimens, determination of HP-status by means of a group of methods, determination of antibodies to H+/K+ -ATPase of parietal cells of the gastric wall, IgG-EA-EBV and IgM-NA-EBN antibodies in the blood serum by means of IFA method, pepsinogene I, pepsinogene II, gastrin and antibodies to Hp with the use of Biohit gastric panel, 24-hour monitoring of intragastric pH with the use of Gastroscan-24 machine. Comparison of all parameters was performed in 4 groups: 27 children aged 6-17 with non-autoimmune gastritis and 119 children with gastritis of other etiology, 34 patients aged 18-80 with autoimmune gastritis and 43 patients of the same age group with non-autoimmune gastritis were described.