[1] Indian Inst Sci, Solid State & Struct Chem Unit, Bangalore 560012, Karnataka, India
[2] Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich, Germany
[3] Forschungszentrum Julich, Inst Adv Simulat, D-52425 Julich, Germany
[4] JARA, D-52425 Julich, Germany
[5] MIT, Dept Phys, Cambridge, MA 02139 USA
[6] MIT, Francis Bitter Magnet Lab, Cambridge, MA 02139 USA