Phase evolution of Zn1-xMnxO system synthesized via oxalate precursors

Polycrystalline samples with nominal composition Zn1-xMnxO have been prepared by a co-precipitation technique in which kinetics of high temperature reactions are favoured by the use of highly reactive particles. Structural and compositional analysis reveal that following the decomposition of the oxalate precursor a secondary ZnMnO3 phase is formed already at 400 degrees C. By means of XRD and HRTEM, a defect spinel-type Structure is presumed for this Zn-Mn-O compound. A diluted magnetic semiconductor in which Mn atoms are homogeneously substituting Zn atoms in the semiconductor matrix is not obtained in the whole temperature range by this synthesis method. The microstructural situation is then far from that theoretically predicted for spintronic systems. (c) 2007 Elsevier Ltd. All rights reserved.