Composition, structure and dielectric properties of multifunctional single-phase Bi1-xLaxFeO3 ceramics

5^th World Congress on Materials Science & Engineering

June 13-15, 2016 Alicante, Spain

Aleksey Pashchenko, Dmitriy Tatarchuk, Nikita Liedienov, Aleksandr Gudimenko, Valeriy Burchovetskii, Yuriy Didenko, Vasyl Prokopenko, Vasy Kladko and Georgiy Levchenko

Donetsk Institute for Physics and Engineering named after O.O. Galkin NASU, Ukraine
National Technical University of Ukraine "KPI", Ukraine
V E Lashkaryov Institute of Semiconductor Physics NASU, Ukraine

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

Composition, structure, microstructure and dielectric properties of the Bi1-xLaxFeO3-�?´ multiferroics were studied by the methods of X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and dielectric spectroscopy. Ceramic samples of the Bi1-xLaxFeO3-�?´ (�?�? = 0, 0.1, 0.3 and 0.5) were prepared by the rapid liquid-phase sintering method. According to the X-ray data the single-phase Bi1-xLaxFeO3-�?´ ceramics have rhombohedral type of crystal structure distortion with changing of lattice parameters and space group from R3m (x = 0) to R3c (�?�? = 0.1), R3m (�?�? = 0.3) and Pnma (x = 0.5). Molar formulas of a real structure Bi1-xLaxFeO3-�?´ have been determined. The real crystal structure is defective and contains anionic V(a) and cationic V(c) vacancies. SEM investigations data have confirmed chemical composition of Bi1-xLaxFeO3-�?´. The microstructure of Bi1-xLaxFeO3-�?´ consists of crystallites which size decreases from 10 to 1 �?¼m with the growth of the concentration x from 0 to 0.5. An analysis of the relative permittivity �?µ(f) and dielectric loss tangent tan�?´(f) frequency dependencies in the low frequency f = 1-106 Hz and microwave f = 8.24-12.05 GHz bands indicates a monotone for �?µ(f) and non-monotonic for tan�?´(f) dispersion. The composition Bi0.9La0.1FeO3 has the greatest value of �?µ(1 Hz) = 5â�?¢105, which decreases to �?µ(1 MHz) = 209 and �?µ(12 GHz) = 10.5. The appearance of two peaks on non-monotonic dependencies of the tan�?´(f) is caused by the presence of relaxation polarization processes in the defect structure of Bi1-xLaxFeO3-�?´.

Biography :

Аleksey Pashchenko is a Doctor of Science at the Phase Transitions Department of the Donetsk Institute for Physics and Engineering named after O.O. Galkin NAS of Ukraine. He has published more than 186 publications, which consist of reputed journals (Acta Mater., J. Magn. Magn. Mater., J. Alloys Comp., etc.), books, patents and abstracts. His main research interests are investigation and determination of structure defects of multiferroics, manganites, nanostructures and novel multifunctional materials.

Email: alpash@mail.ru