1. Laboratory of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland
2. Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland
3. Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland
4. Institute of Physics, Faculty of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland