X-ray studies of magnetism and electronic order in Fe-based materials [Elektronische Ressource] / von Jorge Enrique Hamann Borrero

X-ray Studies of Magnetism and ElectronicOrder in Fe-based MaterialsDissertationzur Erlangung des akademischen GradesDoctor rerum naturalium (Dr. rer. nat.)vorgelegtder Fakult¨at Mathematik und Naturwissenschaftender Technischen Universita¨t DresdenvonJorge Enrique Hamann Borrerogeboren am 28 September 1981 in Medell´ın (Colombia)Dresden 2010ii1. Reviewer: Prof. Dr. Bernd Bu¨chner2. Reviewer: Prof. Dr. Ru¨diger KlingelerthDay of the defense: 17 of December, 2010To my familyiiContents1 Introduction 1I Theory and Experimental Techniques 52 X-ray Scattering by Solids 72.1 Kinematical Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.2 X-ray Magnetic Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.2.1 The Non-Resonant X-ray Magnetic Scattering Cross Section . . . . . . . . 112.2.1.1 X-ray Magnetic Scattering at High Photon Energies . . . . . . . 132.2.2 Resonant X-ray Magnetic Scattering . . . . . . . . . . . . . . . . . . . . . 142.3 Magnetic Superlattice Reflections . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.4 X-ray Diffraction by Powder Samples . . . . . . . . . . . . . . . . . . . . . . . . . 182.4.1 The Rietveld Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.4.1.1 The R Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 Phase Transitions 233.1 Some Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.