Annealing effects on structural and magnetic properties of Co implanted ZnO single crystals
2011 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 8, 083918- p.Article in journal (Refereed) Published
Single crystals of ZnO were implanted with 100 keV-Co ions at room temperature with a fluence of 4.8 x 10(16) cm(-2) and subsequently annealed at different temperatures up to 800 degrees C. The samples were analyzed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, X-ray photoemission spectroscopy and magnetometry. The as-implanted Co:ZnO crystal shows a homogeneous distribution of Co in the near surface region of the crystal. Upon annealing, clear evidence of secondary phases is found. At the highest annealing temperature (800 degrees C) a ferromagnetic behavior is observed at room temperature with a coercive field of 120 Oe assigned mainly to metallic fcc Co nano-crystallites. We find that for the annealed samples, the temperature dependent magnetization cannot be explained within a model containing only a paramagnetic contribution due to well dispersed Co ions and a ferromagnetic contribution due to Co nano-crystallites, at least one more ferromagnetic contribution is needed for a consistent explanation of the experimental results.
Place, publisher, year, edition, pages
2011. Vol. 109, no 8, 083918- p.
FERROMAGNETISM, OXIDES, METAL
IdentifiersURN: urn:nbn:se:kth:diva-33971DOI: 10.1063/1.3559263ISI: 000290047000110ScopusID: 2-s2.0-79955713955OAI: oai:DiVA.org:kth-33971DiVA: diva2:419959
QC 201105302011-05-302011-05-232011-05-30Bibliographically approved