Electron paramagnetic resonance measurements of bulk crystals revealed the presence of a new defect with monoclinic symmetry, in addition to isolated Fe3+ (3d5, S = 5/2). The angular dependence of the resonance lines could be explained only by assuming a spin of S = 5/2, an isotropic g-value of 2.12, and additional fine-structure terms, D and E, with an E/D ratio of 0.091; where D was assumed to be much larger than the microwave quantum. On the basis of resolved hyperfine interactions, the defect was deduced to be an Fe-Ag pair.

P.Christmann, D.Volm, B.K.Meyer, J.Schneider, D.Sinerius, K.W.Benz: Semiconductor Science and Technology, 1995, 10[3], 290-4