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Experimental and Theoretical Investigation of Spin‐Hamiltonian Parameters for the Low Symmetry Fe 3+ Centre in LiNbO 3
Author(s) -
Yeom T. H.,
Chang Y. M.,
Choh S. H.,
Rudowicz C.
Publication year - 1994
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221850211
Subject(s) - electron paramagnetic resonance , hamiltonian (control theory) , superposition principle , ion , spectral line , chemistry , zero field splitting , symmetry (geometry) , atomic physics , molecular physics , condensed matter physics , physics , nuclear magnetic resonance , electron , quantum mechanics , spin polarization , geometry , mathematical optimization , mathematics , organic chemistry
X‐band EPR spectra of Fe 3+ in LiNbO 3 single crystals at room temperature are analyzed with a spin‐Hamiltonian of C 3 symmetry. First the zero‐field splitting (ZFS) parameters b 2 0 , b 4 0 , b 4 3 , and b −3 4 are calculated using the superposition model (SPM). The SPM‐ZFS results for Fe 3+ at the Nb site agree better with the experimental ones than those for Fe 3+ at the Li site. Next the crystal field (CF) parameters are predicted using SPM and two sets of available structural data for LiNbO 3 . Diagonalization of the full Hamiltonian, including the CF Hamiltonian, within the whole 3d 5 configuration yields the ZF splittings for Fe 3+ centres. The ZF splittings obtained from the theoretical SPM‐CF calculations for Fe 3+ at the Nb site agree better with the experimental EPR data than those for Fe 3+ at the Li site. The present results indicate that the observed EPR spectra of Fe 3+ : LiNbO 3 can be attributed to Fe 3+ ions at the Nb sites.