Ferromagnetism and Conductivity in Hydrogen Irradiated Co-Doped ZnO Thin Films

A. Di Trolio, P. Alippi, E.M. Bauer, G. Ciatto, M.H. Chu, G. Varvaro, A. Polimeni, M. Capizzi, M. Valentini, F. Bobba, C. Di Giorgio, A. Amore Bonapasta

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Abstract

Impressive changes in the transport and ferromagnetic properties of Co-doped ZnO thin films have been obtained by postgrowth hydrogen irradiation at temperatures of 400 °C. Hydrogen incorporation increases the saturation magnetization by one order of magnitude (up to ∼1.50 μB/Co) and increases the carrier density and mobility by about a factor of two. In addition to the magnetic characterization, the transport and structural properties of hydrogenated ZnO:Co have been investigated by Hall effect, local probe conductivity measurements, micro-Raman, and X-ray absorption spectroscopy. Particular care has been given to the detection of Co oxides and metal Co nanophases, whose influence on the increase in the transport and ferromagnetic properties can be excluded on the ground of the achieved results. The enhancement in ferromagnetism is directly related to the dose of H introduced in the samples. On the contrary, despite the shallow donor character of H atoms, the increase in carrier density n is not related to the H dose. These apparently contradictory effects of H are fully accounted for by a mechanism based on a theoretical model involving Co-VO(Co-O vacancy) pairs.
Original languageEnglish
Pages (from-to)12925 - 12931
Number of pages7
JournalACS Applied Materials and Interfaces
Volume8
Issue number20
DOIs
Publication statusPublished - 25 May 2016

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Di Trolio, A., Alippi, P., Bauer, E. M., Ciatto, G., Chu, M. H., Varvaro, G., ... Amore Bonapasta, A. (2016). Ferromagnetism and Conductivity in Hydrogen Irradiated Co-Doped ZnO Thin Films. ACS Applied Materials and Interfaces, 8(20), 12925 - 12931. https://doi.org/10.1021/acsami.6b04203