1. The MacDiarmid Institute for Advanced Materials and Nanotechnology
2. Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
3. Instituut voor Kern-en Stralingsfysica, KU Leuven, Leuven, Belgium
4. Laboratory of Solid State Physics and Magnetism, KU Leuven, Leuven, Belgium