1. Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama 35487, USA
2. Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, Alabama 35487, USA
3. Center for Spinelectronic Materials and Devices, Department of Physics, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
4. Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany