E. V. Stukova

Mutual effect of components in ferroelectric composites

The effect of small BaTiO3 particles (2–30 μm) on the ferroelectric properties of TGS in (TGS)1−x-(BaTiO3)x composite and KNO3 in (KNO3)1 − x-(BaTiO3)x composite is studied. It is shown that there is a mutual effect between individual components in the ferroelectric composites that could be due to dipoledipole interaction. The effect of the components in the composites is determined not only by the concentration of particles of inclusions, but also by their size.

Dielectric properties of ferroelectric composites (NaNO2)0.95/(PbTiO3)0.05

ABSTRACT The temperature and frequency dependences of dielectric properties of the ferroelectric composite (NaNO2)0,95/(PbTiO3)0,05 near the phase transition of sodium nitrite have been studied. A significant increase in the real part of the dielectric constant at low frequencies and its strong decrease with increasing frequency were discovered. The temperature hysteresis of phase transition is about 1.5 K. The dielectric constant upon cooling from the paraelectric phase to 273 K is less than during heating, while a similar dependence is observed for conductivity. The results are analyzed in the Landau – Ginzburg theory framework.

Effect of BaTiO3 impurity on the NaNO2 structure in (0.9)NaNO2 + (0.1)BaTiO3 composite

The temperature evolution of the crystalline structure of the composite based on the ferroelectric mixture 0.9NaNO2 + 0.1BaTiO3 is analyzed using the neutron diffraction method. It is shown that the values of the order parameter of NaNO2 in the composite in the temperature range 360–430 K is smaller as compared to the bulk substance, which may indicate the coexistence of the ferroelectric and incommensurate phases of sodium nitrite in this interval.

Structure and dielectric response of (1–x)NaNO2 + xBaTiO3 composites at x = 0.05 and 0.1

The (1–x)NaNO2 + xBaTiO3 composites of two compositions (x = 0.05 and 0.1) have been studied by powder neutron diffraction and broadband dielectric spectroscopy (frequency region 10–1–107 Hz). The temperature dependences of the ferroelectric order parameter of NaNO2 in the composites and pure NaNO2 have been measured. The frequency dependences of the real and imaginary parts of the permittivities of the composites and pure NaNO2 have been analyzed in the temperature range 25–187°C. The anomaly of the dielectric response observed at T ~ 147°C is assumed to be related to the processes of accumulation and “resolution” of charges at the BaTiO3 particle boundaries.

Studies of nanoporous matrices filled with sodium nitrite by nonlinear dielectric spectroscopy

Variation of nanocrystalline NaNO2 properties was studied under the conditions of confined geometry by nonlinear dielectric spectroscopy. It was shown that a decrease in the pore size of silicate matrices MCM-41 filled with NaNO2 leads to an increase of nonlinearity and a change in the shape of the curves of the third harmonic amplitude as a function of temperature.

Nonlinear dielectric properties of NaNO 2 in silicate matrices MCM-41

The properties of NaNO2 in the restricted geometry were studied by nonlinear dielectric spectroscopy. It is shown that for silicate matrices MCM-41 filled with NaNO2, reducing the pore size leads to an increase in the nonlinearity and the change in the shape of the temperature dependence of the amplitude of the third harmonic.