Electronic structure and magnetism of selected materials
Autor: | Chiuzbaian, Gheorghe Sorin |
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Jazyk: | angličtina |
Rok vydání: | 2003 |
Předmět: |
electronic structure
XPS XES metal-organic compounds intermetallic compounds 29 - Physik Astronomie 79.60.-i - Photoemission and photoelectron spectra 71.20.-b - Electron density of states and band structure of crystalline solids 75.30.Et - Exchange and superexchange interactions 75.50.Xx - Molecular magnets ddc:540 |
Druh dokumentu: | Doctoral Thesis |
Popis: | The details of the interplay between the electronic structure and the magnetic properties of matter represent a state of the art challenge. In the present work spectroscopic investigations on the electronic structure of some interesting materials are presented. The achieved information has been used in order to answer specific questions related to the magnetic behavior of the investigated materials. For the transition metal dicyanamide compounds it is shown that the electronic states arising from carbon and nitrogen remain roughly unchanged for all compositions. A model for the magnetic superexchange interaction was proposed. In this model the geometry of the crystallographic structure accounts for a particular interaction pattern while the occupancy of the 3d transition metal band is the factor which triggers the changeover from antiferromagnetic to ferromagnetic interaction. In the case of six-membered ferric-wheel molecules the comparison between experimental and theoretical data issued estimations for the magnitude of magnetic exchange interactions. The information on the electronic structure of the LaNi5-xMex (Me=Cu, Al) allowed a better understanding of their magnetic behavior. The changes induced in the electronic structure of the parent compound by partial substitutions of nickel by copper or aluminum are discussed. |
Databáze: | Networked Digital Library of Theses & Dissertations |
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