# New substitutions and novel derivatives of the Aurivillius phases, $Bi_5TiNbWO_{15}$ and $Bi_4Ti_3O_{12}$

Tripathy, Mamata and Mani, Rohini and Gopalakrishnan, J (2007) New substitutions and novel derivatives of the Aurivillius phases, $Bi_5TiNbWO_{15}$ and $Bi_4Ti_3O_{12}$. In: Materials Research Bulletin, 42 (5). pp. 950-960.

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## Abstract

We investigated isomorphous substitution of several metal atoms in the Aurivillius structures, $Bi_5TiNbWO_{15}$ and $Bi_4Ti_3O_{12}$, in an effort to understand structure–property correlations. Our investigations have led to the synthesis of new derivatives, $Bi_4LnTiMWO_{15}$ (Ln = La, Pr; M = Nb, Ta), as well as $Bi_4PbNb_2WO_{15}$ and $Bi_3LaPbNb_2WO_{15}$, that largely retain the Aurivillius (n = 1) + (n = 2) intergrowth structure of the parent oxide $Bi_5TiNbWO_{15}$, but characteristically tend toward a centrosymmetric/ tetragonal structure for the Ln-substituted derivatives. On the other hand, coupled substitution, $2Ti^{IV} \rightarrow M^V} + Fe^{III}$ in $Bi_4Ti_3O_{12}$, yields new Aurivillius phases, $Bi_4Ti_{3-2x}Nb_xFe_xO_{12} (x = 0.25, 0.50)$ and $Bi_4Ti_{3-2x}Ta_xFe_xO_{12} (x = 0.25)$ that retain the orthorhombic noncentrosymmetric structure of the parent $Bi_4Ti_3O_{12}$. Two new members of this family, $Bi_2Sr_2Nb_2RuO_{12}$ and $Bi_2SrNaNb_2RuO_{12}$ that are analogous to $Bi_2Sr_2Nb_2TiO_{12}$, possessing tetragonal (I4/mmm) Aurivillius structure have also been synthesized.

Item Type: Journal Article Copyright of this article belongs to Elsevier. A. Oxides;A. Layered compounds;C. X-ray diffraction;D. Optical properties Division of Chemical Sciences > Solid State & Structural Chemistry Unit 03 Aug 2007 19 Sep 2010 04:38 http://eprints.iisc.ernet.in/id/eprint/11637