Magnetism of amorphous and highly anisotropic multilayer systems on flat substrates and nanospheres [Elektronische Ressource] / vorgelegt von Edward Prabu Amaladass

iiMagnetism of amorphous and highlyanisotropic multilayer systems on flatsubstrates and nanospheres¨ ¨VON DER FAKULTAT MATHEMATIK UND PHYSIK DER UNIVERSITAT¨STUTTGART ZUR ERLANGUNG DER WURDE EINES DOKTORS DERNATURWISSENSCHAFTEN (DR. RER. NAT.) GENEHMIGTEABHANDLUNGVorgelegt vonEdward Prabu Amaladassgeboren in Thachambady (Indien)Hauptberichter: Prof. Dr. G. Schutz¨Mitberichter: Prof. Dr. G. DenningerTag der mundlic¨ hen Prufung:¨ 10. Dezember 2008Max-Planck-Institut fur¨ Metallforschung, Stuttgart2008ivvI wish to dedicate this thesis to my late grand Father, Mr.M. Mariadoss, Indian Air Force. He taught me to per-severe and prepared me to face challenges with faith andhumility. He was a constant source of inspiration in mylife. Although he is not here to give me strength and sup-port I always feel his presence, which urges me to strive toachieve my goals in life.viviiviiiContents1 Introduction 11.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Aim and outline of the thesis . . . . . . . . . . . . . . . . . . . . 72 Micromagnetic theory 92.1 Energetics of Ferromagnetism . . . . . . . . . . . . . . . . . . . . 92.1.1 Exchange energy . . . . . . . . . . . . . . . . . . . . . . . 92.1.2 Anisotropy. . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.3 Zeeman or external field energy . . . . . . . . . . . . . . . 112.1.4 Magnetostatic energy . . . . . . . . . . . . . . . . . . . . . 112.1.