An electron paramagnetic resonance study was made of Fe2+-doped crystals which had been grown in Cl. This revealed the presence, after X-ray irradiation, the trapped-hole Fecub3+ centers with cubic symmetry that had already been observed in crystals grown under Ar. Also present were Fetrig3+ centers, with axial <111> symmetry. A quantitative analysis of strongly anisotropic X- and Q-band spectra revealed a g-value of 2.0141, and the zero-field splitting parameters: B20 = 800.6, B40 = −0.44, B4−3 = −10.5 and B43 = 0.33  (units of 10−4/cm) at 12K. The particularly large B20 value was suggested to be due to the presence of a charged defect, which replaced one of the 8 nearest-neighbor Cl− ligands. There was an associated off-center displacement of the Fe3+ ion towards it.

EPR of Trigonal Fe3+ Centers in Chlorinated SrCl2:Fe Single Crystals. S.V.Nistor, D.P.Lazar, H.Kass, D.Schoemaker: Solid State Communications, 1997, 104[9], 521-5