1. Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, D-95440 Bayreuth, Germany
2. Bayerisches Geoinstitut Universität Bayreuth, D-95440 Bayreuth, Germany
3. Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden