New synthesis routes for obtaining dysprosium manganese perovskites

Dysprosium manganese perovskite DyMnO3+delta has been synthetized via thermal decomposition of polynuclear coordination compound precursors, containing as ligands polyhydrocarboxylic acid anions (malic, tartric and gluconic). The evolution of crystal symmetry has been interpreted by considering the effect of the Mn4+ content, which depends on the nature of the precursor, namely the complexing agent. DyMnO3+0.07 generated from a malic precursor presents an orthorhombic structure. In DyMnO3+0.13 obtained from a tartric compound a two-phase mixture of the orthorhombic and hexagonal structure is detected. A pure hexagonal compound DyMno(3+0.20) is obtained from a gluconic derived oxide. (C) 2002 Elsevier Science B.V. All rights reserved.