Orbital Ordering and Multiferroics

Orbital Ordering and Multiferroics
byGwilherm Nenert

Orbital Ordering and Multiferroics

PhD Thesis By Gwilherm Nenert

University of Groningen, The Netherlands.

2007

Printed by: Facilitair Bedrijf RuG, Groningen
ISBN 97-367-2973-4
Zernike Institute for Advanced Materials Ph.D.-thesis series 2007-06
ISSN 1570-1530

The work described in this thesis was performed in the group "Solid State Chemistry" (part of the Zernike Institute for Advanced Materials) of the University of Groningen, the Netherlands.

Transition metal oxides can exhibit a wide variety of properties which can be tuned by changing factors such as composition, magnetic field and temperature. The complex physical phenomena involved can give rise to functional materials such as magnetic field sensors or ferroelectrics. The discovery of new functional materials is a challenge for the development of smart systems. To guide this search, a clear understanding of the relationship between the physical properties and the atomic scale structure of the materials is needed. Of fundamental importance is the crystal chemistry of a given compound. Crystal chemistry refers to two aspects: symmetry and the distribution of atoms in the unit cell.

The crystal chemistry can be investigated by means of synchrotron X-ray and neutron diffraction. These techniques provide information that can be used as a starting point for a better understanding of the physical properties. The physical properties are directly related to the symmetry exhibited by the system. Thus the symmetry is an important tool to investigate materials of interest.