Electron Paramagnetic resonance studies of isolated Iron (Fe3+ ) Ions in SrTiO3 Crystals at 80 K
The Electron Paramagnetic Resonance (EPR) study of the iron ions are very important where these paramagnetic centres show several desired properties when doped in the host STO (SrTiO3) crystal. It leads to highly disordered local states, highly conductivity, change the STO from semiconductor to conductor, ferromagnetic, and ferroelectric transition at local symmetry low. This sample can be used in detectors, receivers, transistor, thin film and Non-Volatile Ferroelectric Random-Access Memories (NVFRAMs).
This study present 9 GHz band EPR of 
ions in the monodomain STO (SrTiO3) crystals at 80 K and magnetic field up to 2T. This paper considers both experimental and theoretical studies of EPR of ions in STO crystals. It includes determine of the structure of the phase transition, and Spin Hamiltonian (SH) parameters. The simulation programme was written to simulate the experimental results and the energy levels for these transitions. This program allows an inference of the local structure of the position of paramagnetic ions in STO crystal, and finds the experimental value of SH parameters.
At 80 K the Fe3+ Ions have tetragonal structure or symmetry C4v in tetragonal phase of STO crystals. The position of isolated Fe3+ ions is nearly in the centre (
) with contraction 13%. The splitting in the lines are fifteen lines distribution in three groups ( inner, outer, and center group) along range from 300 mT to 400 mT. These lines coming from six defect centers paralleled and tilted from <100> by rotation angle
. The transitions between energy levels are coinciding to these five transitions
.
Keywords: monodomain, phase transition, tetragonal, rotation angle.