A. S. Sidorkin

Properties of nanoporous aluminum oxide with triglycine sulfate and Rochelle salt inclusions

The possibility of producing the ferroelectric state in nanoporous aluminum oxide loaded with triglycine sulfate and Rochelle salt has been studied. Our dielectric, pyroelectric and emission measurements give grounds to suggest that this state persists in the composites under study up to temperatures exceeding the Curie point of bulk crystals by several tens of degrees.

Dielectric Properties of Ferroelectric Composites with TGS Inclusions

Dielectric properties of composites consisting of nanoporous aluminium oxide Al2O3 or glass SiO2 with inclusions of the ferroelectric triglycine sulphate (TGS) are investigated in the present work. Our investigations enable us to assume the presence of ferroelectric state in these materials.

Synthesis and Study of Dielectric Properties of PbTiO 3 Thin Films

A new way of synthesis of ferroelectric films of lead titanate is presented which is based on solid-phase reaction in oxygen ambient between the layers of titanium and lead deposited by magnetron sputtering onto a substrate. Dielectric properties of synthesized films have been investigated. Temperature dependence of dielectric permeability, as well as temperature and thickness dependences of coercive field in the investigated films were shown to be of the type that is characteristic of ferroelectric materials.

Dielectric Properties of Composites Based on Nanocrystalline Cellulose and Triglycine Sulfate

This paper is devoted to studies of properties of composites based on nanocrystalline cellulose and triglycine sulfate. The presence of one or two peaks in the temperature dependence of dielectric permittivity was revealed and their shift to higher temperatures as compared with the bulk TGS to 54°C and 100°C was detected, respectively. An explanation of the results is related to the appearance of internal bias fields in the nanocomposites.

Fatigue of Lead Titanate and Lead Zirconate Titanate Thin Films

The fatigue of lead titanate and lead zirconate titanate ferroelectric thin films, i.e., a change in the polarization as a function of the number of switching cycles in an external electric field, is investigated experimentally. The threshold numbers of switching cycles are determined to be 1010–1011 for the lead titanate films and 109–1010 for the lead zirconate titanate films. It is shown that a change in the temperature does not substantially affect the threshold number of switching cycles at which the switched polarization decreases drastically. However, an increase in the external field strength leads to a noticeable decrease in the threshold number of switching cycles. The process of fatigue is accompanied by an increase in the coercive field and the internal bias field. It is established that, as the number of switching cycles increases, the internal bias field changes more significantly as compared to the coercive field. The absence of a change in the phase composition in repeatedly switched samples indicates that the fatigue processes have a nonchemical nature. The anomaly observed in the frequency dependence of the permittivity in the frequency range 106–107 Hz due to the domain structure disappears after multiple switching cycles. This suggests that the observed fatigue phenomenon has a domain nature.

Dielectric properties of lead titanate thin films on corundum substrates

Ferroelectric films of lead titanate were synthesized on corundum (Al2O3) substrates. The main parameters that characterize the dielectric hysteresis, such as the spontaneous polarization, coercive force, internal bias field, and the phase-transition temperature, were determined. The dispersion of the permittivity was studied using impedance spectroscopy in wide temperature and frequency ranges. An anomaly in the frequency dependence of the complex permittivity was revealed at frequencies of the order of 107 Hz.

APPEARANCE OF INTERNAL BIAS FIELD IN FERROELECTRIC GROWTH PROCESS

Abstract The growth regularities of the internal bias field Eb formation have been investigated in pure triglycine sulphate crystals, as well as in crystals doped with chromium or α-alanine. All crystals were grown in the ferrophase from the seed of the pivot form oriented by its axis along the non-polar crystal axis Z. It was found that the bias field had different signs in the samples lying on opposite sides of the seed along the polar axis Y in the crystals with chromium impurity and pure crystals and the same sign in α-alanine doped ones. The probable mechanism of Eb field formation is suggested for both cases.

The “freezing” of the domain structure in the CDP crystal resulting from the structural reconstruction of the domain walls

Investigations of the dielectric and pyroelectric properties of CDP crystals are reported. The data confirm domain structure mechanism connected with structural reconstruction of domain walls.

Dielectric properties of composites based on nanocrystalline cellulose with triglycine sulfate

The dielectric properties and frequency dispersion of the dielectric characteristics of nanocrystalline cellulose-triglycine sulfate composites have been studied in the low- and infralow-frequency ranges (from 10−3 to 103 Hz) in a weak electric field. It has been shown that the phase transition in these composites is diffuse and displaced to the higher temperatures range as compared to the transition in bulk triglycine sulfate. In the composites under study, a significant dispersion of the permittivity, presumably caused by a positive Maxwell-Wagner relaxation, is observed.

Structure and Electrical Properties of Nanocomposites with TGS Inclusions

The structure and properties of nanocomposite structures based on porous matrix with a triglycine sulfate inclusions have been investigated. Interrelation between the behavior of the dielectric parameters (dielectric susceptibility, the Curie temperature) and structural features of the composite has been established. It is shown that changing the size of ferroelectric inclusions and their relative positions may have a significant effect on the phase transition temperature.