Comparative study of structure, dielectric and electrical behavior of Ba(Fe0.5Nb0.5)O3 ceramics and their solid solutions with BaTiO3

N.K. Singh1, Pritam Kumar1, Radheshyam Rai2*

1University Department of Physics, V. K. S. University, Ara 802301 Bihar, India

2Department of ceramics and glass engineering and CICECO, University of Aveiro, 3810-193 Aveiro, Portugal

Adv. Mater. Lett., 2011, 2 (3), pp 200-205

DOI: 10.5185/amlett.2010.11178

Publication Date (Web): Apr 08, 2012

E-mail: radheshyamrai@ua.pt?

Abstract


Dielectric properties of (1-x)Ba(Fe0.5Nb0.5)O3-xBaTiO3 (where x = 0.00, 0.05 and 0.10) solid solution ceramics at high temperature range of RT ~ 270 oC have been characterized in this paper. The above said polycrystalline ceramics with (x = 0.0, 0.05 and 0.10) have been produced via a mixed oxide route. The effects of BaTiO3 substitution on the structure and on the electrical and ferroelectric properties of Ba(Fe0.5Nb0.5)O3 samples have been studied by performing x-ray diffraction and dielectric measurements. The dielectric properties (e¢ and tan d) were investigated in the temperature range of 30-270 °C and in the frequency range of 100 Hz-5 MHz. The variation of relative dielectric permittivity (tan d) and tangent loss (tan d) has suggested a significant role of hopping of trapped charge carriers, which is resulted in an extra dielectric response in addition to the dipole response. It is observed that: (i) the relative dielectric permittivity and tangent loss (tan d) are dependent on frequency, (ii) the temperature of dielectric permittivity maximum shifts toward lower temperature side and (iii) dielectric permittivity and tangent loss rapidly increase by making solid solution of BFN with BaTiO3. X-ray diffraction analysis of the compound suggests the formation of single-phase compound with monoclinic structure. SEM photographs exhibit the uniform distribution of grains. The maximum ferroelectric transition temperature (Tc) of this system was 250-270 °C with the dielectric constant peak of 72500 at 1.09 kHz for x = 0.05.

Keywords

Ceramics, scanning electron microscopy, X-ray diffraction, dielectric properties

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