1. Hitachi-ABB Power Grids, Fabrikstrasse 3, 5600 Lenzburg, Switzerland
2. National Center of Microelectronics, CNM-CSIC, Barcelona Campus, Bellaterra-Barcelona, Spain
3. Lawrence Livermore National Laboratory, Livermore, California 94550, USA
4. Center for Material Science and Nanotechnology, University of Oslo, N-0316 Oslo, Norway