Electron paramagnetic resonance of Fe3+ in LiNbO3

NOTE: THE MATHEMATICAL SYMBOLS/SPECIAL CHARACTERS IN THIS ABSTRACT CANNOT BE DISPLAYED CORRECTLY ON THIS PAGE. PLEASE REFER TO THE ABSTRACT ON THE PUBLISHER’S WEBSITE FOR AN ACCURATE DISPLAY. We report electron paramagnetic resonance (EPR) experiments on the dominant Fe3+ center in high-quality near stoichiometric LiNbO3 grown from a Li/Nb ratio controlled melt. Symmetry related line splittings were clearly resolved and allowed unambiguous determination of the relative signs and magnitudes of the fourth-order trigonal zero field splitting (ZFS) spin-Hamiltonian (SH) parameters. Two conflicting EPR C3 symmetry SHs for this center have been previously reported. Approximate agreement was found with that obtained for near-stoichiometric LiNbO3 grown using a K2O flux [G. I. Malovichko et al., J. Phys.: Condens. Matter 5, 3971 (1993)]. Extensive superposition model calculations of ZFS-SH terms showed that small displacement from either the Li or the Nb host site allowed the experimental rank-2 parameter value to be reproduced. Hence, on the basis of the EPR ZFS values alone, it is not currently possible to distinguish between possible C3 incorporation sites within either the Li or Nb octahedra. © 2005 The American Physical Society