EPR study of Fe3+ paramagnetic centers in doped triglycine sulphate crystals

This paper presents EPR study of Fe3+ in Triglycine sulphate doped with Fe3+ crystal. Fe3+ ions is in a high spin state S = 5/2. EPR signal can be detected only below 200 K.; At 4.2 K the EPR spectrum results from three non-equivalent sites of Fe3+ ions. The spin Hamiltonian: H = βBgS +D[S2z-(1/3)S(S+1)]+E(S2x-S2y) has been applied to describe the spectrum. The zero field splitting parameter in this case fulfills the condition: D>>hν. An experimental spectrum reflects clearly only two resonance transitions: |±1/2> (the lowest Kramers doublet) and +/- 3/2 (the middle Kramers doublet). The iron complexes occupy interstitial positions in the crystal with distorted octahedral or tetrahedral co-ordination. (author)