Structural and dielectric properties of ferroelectric $Sr_1_-_xBa_xBi_2(Nb_0_._5Ta_0_._5)_2O_9$ and $Sr_0_._5Ba_0_._5Bi_2(Nb_1_-_yTa_y)_2O_9$ ceramics

Prasad, Syam N and Varma, KBR (2003) Structural and dielectric properties of ferroelectric $Sr_1_-_xBa_xBi_2(Nb_0_._5Ta_0_._5)_2O_9$ and $Sr_0_._5Ba_0_._5Bi_2(Nb_1_-_yTa_y)_2O_9$ ceramics. In: Materials Research Bulletin, 38 (2). pp. 195-206.

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Abstract

Ferroelectric $Sr_1_-_xBa_xBi_2(Nb_0_._5Ta_0_._5)_2O_9$and $Sr_0_._5Ba_0_._5Bi_2(Nb_1_−_yTa_y)_2O_9$ were synthesized by solid state reaction route. X-ray diffraction studies confirm the formation of single phase layered perovskite solid solutions over a wide range of compositions (x=y=0.0, 0.25, 0.50, 0.75 and 1). The lattice parameters and the Curie temperature $(T_c)$ have been found to have linear dependence on x and y. Transmission electron microscopy (TEM) suggest the lowering of orthorhombic distortion with increasing $Ba^2^+$ substitution. Variations in microstructural features as a function of x and y were monitored by scanning electron microscopy (SEM). The dielectric constant at room temperature increases with increase in both x and y. Interestingly $Ba^2^+$ substitution on $Sr^2^+$ site induces diffused phase transition and diffuseness increases with increasing $Ba^2^+$ concentration.

Item Type:	Journal Article
Publication:	Materials Research Bulletin
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Ceramics;Electron microscopy;X-ray diffraction;Dielectric properties;Ferroelectricity
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	02 Jun 2006
Last Modified:	19 Sep 2010 04:28
URI:	http://eprints.iisc.ac.in/id/eprint/7329

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