Analysis of the vibrational properties of Zn1-xCoxO by Raman spectroscopy

Currently, ZnO-based diluted magnetic semiconductors (DMS) attract much attention, mainly because of the predicted possibility of ferromagnetism at 300 K. Among these materials, Zn1-xCoxO takes a prominent position. In spite of numerous investigations, a general understanding of its magnetic propert...

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Published inJournal of physics. Conference series Vol. 92; no. 1; p. 012149
Main Authors Schumm, M, Koerdel, M, Morhange, J F, Golacki, Z, Grasza, K, Skupinski, P, Szuszkiewicz, W, Zhou, H, Malik, V, Kalt, H, Klingshirn, C, Geurts, J
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.12.2007
Subjects
Ferromagnetism
Lattice vibration
Magnetic properties
Magnetic semiconductors
Mixed crystals
Physics
Precipitates
Raman spectra
Raman spectroscopy
Thin films
Vibration mode
Zinc oxide
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Summary:Currently, ZnO-based diluted magnetic semiconductors (DMS) attract much attention, mainly because of the predicted possibility of ferromagnetism at 300 K. Among these materials, Zn1-xCoxO takes a prominent position. In spite of numerous investigations, a general understanding of its magnetic properties is still missing. Moreover, its detailed magnetic behavior depends on the sample fabrication and after growth treatment. We present a systematic analysis of structural Zn1-xCoxO properties by micro-Raman scattering for a wide variety of different sample parameters. Bulk mixed crystals (x < 0.05) and thin layers (0.03 < x < 0.12) were investigated between 1.6 K and 295 K. Beside the common eigenmodes of the ZnO host lattice, we observe disorder-induced lattice vibration modes and structures, which we assign to vibration modes of Co-related precipitates. We present their dependence on the composition, the applied preparation technique, and the annealing process. Furthermore, the possible impact of such precipitate formation on the magnetic properties is discussed.
ISSN:1742-6596
1742-6588
1742-6596
DOI:10.1088/1742-6596/92/1/012149