Bismuth-induced dielectric relaxation in the (1-x)La(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xBi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3} perovskite system

Journal Article · Tue Jul 01 00:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2951890· OSTI ID:21137387

Salak, Andrei N ^[1]; Ferreira, Victor M ^[2]; Ribeiro, Jose L; Vieira, Luis G ^[3]; Pullar, Robert C; Alford, Neil McN ^[4]

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1. Department of Ceramics and Glass Engineering/CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)
2. Department of Civil Engineering/CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)
3. Department of Physics, University of Minho, 4710-057 Braga (Portugal)
4. Centre for Physical Electronics and Materials, Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

The temperature variation of the dielectric permittivity and loss of the solid solutions (1-x)La(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xBi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3} [(1-x)LMT-xBMT] (0{<=}x{<=}0.3) measured at radio, microwave, and far infrared frequency ranges has been analyzed in comparison with that observed in other bismuth-containing and bismuth-free perovskite ceramics based on LMT. It has been found that the low temperature dielectric response of the (1-x)LMT-xBMT compositions with x{>=}0 is frequency dependent over a wide range from radio to microwave frequencies. The considerable compositional growth of the dielectric permittivity and loss associated with the amount of bismuth in the system was revealed to be not contributed by the lattice polar phonon modes. The effect was suggested to be related to the low-temperature dielectric relaxation process due to a hopping movement of charge carriers in crystallographic A-sites of the perovskite lattice. Particular role of local lattice distortions caused by the anisotropic chemical bonds involving bismuth 6s{sup 2} electrons in a localization of hopping charge carriers in perovskites and other oxygen-octahedral compositions is considered. The characteristic features of the Bi-induced dielectric relaxation and those typical of the ferroelectric relaxors are compared and discussed.

• OSTI ID: 21137387
• Journal Information: Journal of Applied Physics, Vol. 104, Issue 1; Other Information: DOI: 10.1063/1.2951890; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
BISMUTH
BISMUTH COMPOUNDS
CERAMICS
CHARGE CARRIERS
CHEMICAL BONDS
CRYSTAL GROWTH
CRYSTALLOGRAPHY
FERROELECTRIC MATERIALS
FREQUENCY DEPENDENCE
INFRARED SPECTRA
LANTHANUM COMPOUNDS
MAGNESIUM COMPOUNDS
MICROWAVE RADIATION
MICROWAVE SPECTRA
PERMITTIVITY
PEROVSKITE
SOLID SOLUTIONS
TITANATES