Materials Research Bulletin, Vol.40, No.1, 39-45, 2005
Transformation of Dion-Jacobson phase to Aurivillius phase: synthesis of (PbBiO(2))MNb(2)O(7) (M = La, Bi)
We describe transformations of the Dion-Jacobson (D-J) phases, KLaNb(2)O(7) and RbBiNb(2)O(7), to the Aurivillius (A) phases, (PbBiO(2))LaNb(2)O(7) (1) and (PbBiO(2))BiNb(2)O(7) (2), in a metathesis reaction with PbBiO(2)Cl. Oxide 1 adopts centrosymmetric tetragonal structure (a = 3.905(1) Angstrom, c = 25.66(1) Angstrom), whereas oxide 2 crystallizes in a noncentrosymmetric orthorhombic (A2(1)am) (a = 5.489(1) Angstrom, b = 5.496(2) Angstrom, c = 25.53(1) Angstrom) structure. Oxide 2 shows a distinct SHG response towards 1064 nm laser radiation. The role of La 3, versus Bi(3+) in the perovskite slabs for the occurrence of noncentrosymmetric structure/ferroic property in these materials is pointed out. (C) 2004 Elsevier Ltd. All rights reserved.