International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

Search for the Formation of Magnetic Nanoclusters by Ion Implantation into Suitable Insulators

K. Bharuth-Ram^1,2, T.B. Doyle^1,2, H. Hofsäss³, S. Müller³, and C. Ronning⁴

¹School of Physics, University of KwaZulu-Natal, Durban, South Africa
²iThemba LABS, Somerset West, Western Cape, South Africa
³Zweites Physikalisches Institut, UniversitÄt Göttingen, Göttingen, Germany
⁴Institute for Solid State Physics, University of Jena, Jena, Germany

Corresponding Author: kbr@tlabs.ac.za

Ion beams are finding increasing applications in the synthesis and modifications of materials on the nanometer scale. Strict control of ions species, energy and fluence allow one to tailor the ion irradiation conditions to specific applications and circumvent restrictions set to ion solid interactions by thermodynamic effects. We report on our search for the formation of magnetic nanostructures in suitable host matrices, achieved by the implantation of low fluence Fe ions accelerated to 60-80 keV energy. Mass separated Fe⁵⁷ions were implanted to fluences of 5 x 10¹⁵, 1 x 10¹⁶ and 2 x 10¹⁶ per cm², into ZnO, 3C-SiC and SiO₂ substrates. The search for cluster formation was conducted as functions of thermal treatment of the substrates and implantation dose. Characterization methods included Mössbauer spectroscopy, Rutherford Backscattering Spectrometry, and MOKE and VSM measurements.

The Mössbauer spectra of the Fe implanted ZnO and SiC single crystals, annealed up to 1073K and 973K, respectively, show that the Fe³⁺ ions remain fairly constant in the crystals, while the Fe²⁺ show some reordering. Evidence of formation of ferromagnetic clusters is obtained on ZnO samples implanted with Fe⁵⁷ at several energies giving a plateau distribution. These results will be presented and discussed.

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