Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 48: ZnO: Preparation and characterization II
HL 48.1: Talk
Thursday, February 28, 2008, 09:30–09:45, ER 164
Characterization of Mn doped ZnO Nanopowder — •Eva Schlenker1, Andrey Bakin1, Herbert Schmid2, Werner Mader2, Heiko Bremers3, Andreas Hangleiter3, Mohamed Al-Suleiman1, Hergo-Heinrich Wehmann1, and Andreas Waag1 — 1Institute of Semiconductor Technology, TU Braunschweig, 38106 Braunschweig — 2Institute for Inorganic Chemistry, University of Bonn, 53117 Bonn — 3Institute of Applied Physics , TU Braunschweig, 38106 Braunschweig
In the quest of materials for spintronic applications, diluted magnetic semiconductors recently attracted much attention. The main challenge is finding a ferromagnetic material with Curie temperature Tc > 300 K whose magnetic properties can be controlled electrically. The interest was particularly focused on Zn(TM)O since theoretical calculations predict that ZnO containing Mn could exhibit ferromagnetism with Tc above room temperature. In the present study, the structural and magnetic properties of Mn doped ZnO nanopowder are investigated and compared to undoped ZnO crystals. Doping of ZnO with Mn results in increased lattice constants as revealed by XRD. However, an inhomogeneous distribution of the Mn dopants within the nanopowder was revealed by energy-dispersive X-ray and electron energy-loss spectroscopy. Magnetic properties are investigated by means of SQUID measurements on aggregates of powder particles as well as by MFM to study the behavior of single grains. The MFM image differs significantly from the topography as imaged by AFM and suggests the existence of long-ranging magnetic signals emerging from the sample.