Electron paramagnetic resonance studies of the iron ions in strontium titanate oxide crystals

Thesis

2006

Booq, zainab . 2006

Abstract
 Electron paramagnetic resonance (EPR) is a unique technique to gain knowledge about paramagnetic ions in materials, including its positions, the local arrangement of atoms around the paramagnetic centre, and the energy level splittings for the ground state of the centre. Studies of the paramagnetic ion, Fe3+, in SrTiO3 have been the subject of a large number of EPR papers. However, there remains considerable uncertainty regard the values of the spin Hamiltonian parameters and the interpretation of the low temperature spectra.
This thesis presents 9 GHz band EPR of Fe3+ ions in the monodomain SrTiO3 crystals though the temperature range 300 to 15 K. Magnetic fields up to 2 T were used. This thesis considers both experimental and theoretical studies of EPR of Fe3+ ions in SrTiO3 crystals. It includes analysis of the structure of the phase transitions, spin Hamiltonian parameters, and the variation of many of these parameters with temperature. The simulation program is written to simulate all the experimental results in this thesis including newly discovered lines for the  centres, and the energy levels for these transitions. This program allows an inference of the local structure of the position of the paramagnetic ions in SrTiO3 crystal, and finds the experimental value of SH parameters. This program suggests the existence of a new region of short-range order for Fe3+ ions in SrTiO3 crystal. The Superposition Model is used with a new mathematical model in this thesis to infer a position for the paramagnetic ions, and to determine the theoretical values for SH parameters

• Publication Work Type: PHD thesis
• Publishing City: Dundee University, Dundee, UK,
• Thesis Type: PHD thesis