Laboratory of Physics of Oxide Ferroelectrics

The main task of the FOS laboratory is to obtain new magnetoelectric composite materials (so-called "composite multiferroics") based on oxide ferroelectrics with an ordered domain structure, as well as to study the properties of such materials and create devices and devices based on them. The objects of research are composite multiferroics based on bulk mono- and polycrystalline, as well as thin-film ferroelectrics, amorphous metal glasses, thin films and foils of ferromagnetic metals and alloys, as well as binding materials. Among the possible applications of composite multiferroics, one of the most promising and close to practical implementation is the creation of highly sensitive ultra-weak magnetic field sensors based on such materials, capable of operating at room temperature and allowing contactless measurement of ultra-weak currents in low-power devices and electronic circuits, as well as in living organisms.

One of the possible applications, due to which volumetric and composite magnetoelectrics have been intensively studied in recent years by many leading world scientific groups, is the possibility of using them in noninvasive diagnostic devices as sensors of ultra-weak magnetic fields induced by currents flowing in the neurons of living organisms (in particular, in the heart and central nervous system). Thus, magnetoencephalographs and magnetocardiographs allow early diagnosis, localization and study of such diseases of the brain and heart as multiple sclerosis, Alzheimer's disease, schizophrenia, chronic alcoholism, neuralgia of various genesis, myocardial infarction, arrhythmia. The creation of new magnetoelectric materials based on oxide ferroelectrics with an ordered domain structure will make it possible to reduce the cost of existing magnetic diagnostic devices, which will contribute to their wide dissemination and application in medical practice. The simplicity of manufacturing and the possibility of miniaturizing the structure of this type will allow you to create more affordable magnetic diagnostic devices. Other promising devices using active elements based on composite multiferroics are microwave phase shifters, electronically tunable microwave resonators and delay lines, waste energy collection systems, and magnetoelectric gyrators. The main scientific activities of the laboratory are the development of numerical methods for calculating the magnetoelectric parameters of layered composite magnetoelectrics. Investigation of the influence of the domain structure of the ferroelectric phase on the properties of magnetoelectric composites.

Development of a technique for the local formation of charged inter-domain boundaries in bulk single crystals of 180-degree ferroelectrics LiNbO3 and LiTaO3 and the study of the electrophysical properties of such boundaries. Synthesis and study of thin films of lead-free ferroelectrics (including nanocrystalline ones), development of methods for controlling the domain structure of such films in order to increase the magnetoelectric properties of composites based on them. Synthesis and investigation of thin films of magnetostrictive materials by laser ablation, magnetron sputtering of the target and electrochemical deposition. Investigation of the effect of various magnetostrictive materials (amorphous metallic glasses, thin nickel films) on the magnetoelectric properties of composite structures. Calculation and formation of an optimal domain structure in LiNbO3 and LiTaO3 ferroelectrics in order to increase the magnetoelectric effect, reduce internal thermal noise and miniaturize the functional layers of magnetoelectric composites Development of a technique for obtaining composite thin-film structures with ferroelectric and magnetoelectric inclusions based on chemical deposition from a vapor-gas medium in vacuum. Investigation of ferroelectric and magnetoelectric nanoscale clusters in composites based on amorphous ligature-resistant materials in high concentrations. Determination of the fundamental aspects of the formation of ferroelectric and magnetoelectric thin layers in composites based on an amorphous ligature resistant to incorporation in high concentrations of the matrix. Development of methods for studying the electrophysical parameters of the obtained multimagnetic thin-film materials. Investigation of the static domain structure, effects of local polarization switching, measurement of piezoelectric characteristics of lead-free ferroelectric ceramics, including those based on potassium-sodium niobate (K0.5Na0.5)NbO3 and barium titanate zirconate (Ba(Zr,Ti)O3) by scanning probe microscopy.

Comparative analysis of the effect of iso- and heterovalent substitutions on dielectric parameters, the magnitude of spontaneous polarization and piezoelectric characteristics, identification of compositions that are most promising in terms of practical applications.

Creation of functional elements for sensors of ultra-weak magnetic fields induced by currents flowing in the neurons of living organisms (in particular, in the heart and central nervous system), in non-invasive diagnostics.