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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.99: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

Absence of ferromagnetism in V-implanted ZnO single crystals — •Shengqiang Zhou, Kay Potzger, Helfried Reuther, Karsten Kuepper, Wolfgang Skorupa, Manfred Helm, and Juergen Fassbender — Institute for Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, POB 510119, 01314 Dresden, Germany

Diluted magnetic semiconductors (DMS) have recently attracted huge research attention because of their potential application for spintronics devices [1]. ZnO doped with V was found to be ferromagnetic at room temperature [2]. However, the origin of the observed ferromagnetism in transition metal doped ZnO is still controversial, e.g. ferromagnetic clusters [3], or extrinsic reasons [4]. In this paper the structural and magnetic properties of V doped ZnO are presented. V ions were introduced into hydrothermal ZnO single crystals by ion implantation with fluences of 1.2*10^16 to 6*10^16 cm^-2. Post-implantation annealing was performed in high vacuum from 823 K to 1023 K. The ZnO host material still partly remains in a crystalline state after irradiation, and is partly recovered by annealing. The V ions show a thermal mobility as revealed by depth profile Auger electron spectroscopy. Synchrotron radiation x-ray diffraction revealed no secondary phase formation which indicates the substitution of V onto Zn site. However in all samples no pronounced ferromagnetism was observed down to 5 K by a superconducting quantum interference device magnetometer.

1.T. Dietl, et al., Science 287, 1019 (2000). 2.N. H. Hong, et al., J. Phys.: Condens. Matter 17, 199 (2005). 3.J. H. Park, et al., APL 84, 1338 (2004). 4.D. W. Abraham, et al., APL 87, 252502 (2005).