Alexey Zayak :

A first-principles investigation of the magnetic, structural and dynamical properties of Ni2MnGa

Dissertation angenommen durch: Universität Duisburg-Essen, Campus Duisburg, Fakultät für Naturwissenschaften, Institut für Physik, 2003-11-24

BetreuerIn: Prof. Dr. Peter Entel , Universität Duisburg-Essen, Campus Duisburg, Fakultät für Naturwissenschaften, Institut für Physik

GutachterIn: Prof. Dr. Peter Entel , Universität Duisburg-Essen, Campus Duisburg, Fakultät für Naturwissenschaften, Institut für Physik
GutachterIn: Prof. Dr. Roland Feder , Universität Duisburg-Essen, Campus Duisburg, Fakultät für Naturwissenschaften, Institut für Physik

Schlüsselwörter in Englisch: Heusler alloys, Martensite, Modulation, Phonons, Ginzburg-Landa

  
   
 Klassifikation     
    Sachgruppe der DNB: 530 Physik
  
   
 Abstrakt     
   

Abstrakt in Englisch

This is a theoretical investigation of the magnetic, structural and dynamical properties of the ferromagnetic Heusler compound Ni-Mn-Ga. Its physical properties have been studied by means of the Density Functional Theory. The challenge of this work is to explain in terms of the electronic structure and phonon spectra the entire variety of different crystal structures of Ni-Mn-Ga and their stability. It was shown that this crystal exibits anomalies both in the electronic structure and the phonons. Important for Ni-Mn-Ga features include modulation shuffling of the structure, phonon softening, phonon acoustic-optical coupling, electron-phonon coupling and the charge transfer. A combination of these properties allowed to draw a solid physical view on the nature of the Heusler alloys and the alloy Ni-Mn-Ga. A first-principles investigation of the magnetic, structural and dynamical properties of Ni2MnGa