An electron paramagnetic resonance investigation was made of trivalent Gd impurities in single crystals. Intense resonance lines in the spectrum were attributed to a center which was produced by the incorporation of Gd3+ at Mg2+ sites. The electron paramagnetic resonance spectrum of this center could be satisfactorily explained in terms of a spin Hamiltonian with monoclinic symmetry and S = 7/2. All of the non-zero g-matrix components and fine-structure parameters for this center were determined by using a least-squares procedure.

D.Bravo, K.Polgár, F.J.López: Solid State Communications, 1997, 103[2], 65-9