Tin dioxide lms with variable stoichiometric composition were fabricated by means of dc magnetron sputtering followed by a 2-stage annealing process. The structural and electrical properties of tin dioxide lms were investigated by means of the Raman spectroscopy and impedance spectroscopy, respectively. It was found that crystallinity and grain size of tin dioxide lms increase with the increasing annealing temperature. The most conductive samples were obtained at the annealing temperature 375• C. Increasing of the impedance of lms annealed at higher temperatures is explained by decrease of the concentration of oxygen vacancies.

No abstract

The composite material filled with nano-sized BaTiO3 and Fe3O4 was designed and studied. The aluminium phosphate ceramics was used as a matrix. The XRD analysis demonstrates only the crystalline structure of the fillers used. The thermogravimetric analysis proves the thermal stability of the composites up to 950 K. The Maxwell–Wagner relaxation was observed in the dielectric spectra of the investigated composites. The dielectric spectroscopy proves the close contact between the nanoparticles with the different ferroic ordering. The phosphate-based composites have been proved to be a prospective candidate for the multiphase multiferroic materials design and development.

The electromagnetic properties of chloroprene rubber after long-term ultraviolet ageing, oil immersion and thermal degradation were experimentally investigated in the frequency range from 1 kHz up to 1 THz. Ageing was shown in terms of mechanical degradation and the change in the complex dielectric permittivity. Within the whole investigated frequency range decrease of dielectric permittivity was observed after thermal treatment combined with oil immersion in comparison with chloroprene rubber stored under normal conditions. In contrast, thermal and ultraviolet ageing without immersion leads to increase of rubbers dielectric permittivity in all investigated frequency ranges. A non-invasive express method of degradation detection is proposed and proofed.