The electron spin resonance of Cu and Eu was investigated in the case of the joint activation of layered crystals. These impurities were chosen because of their marked effect upon the light-sensitive properties of the present iodide. It was found that the Cu was in a non-paramagnetic state, in the form of CuCd+ and Cui+, due to the reducing effect of I upon the Cu ions. On the basis of the angular dependences of the electron spin resonance of Eu, it was shown that it was in the doubly-charged state, that it exhibited an axial symmetry of D3d, that it replaced Cd at a lattice site, and that it was not found in other positions: such as interstices and inter-layers. The g factor and constants of the spin Hamiltonian were determined in the first approximation of perturbation theory. The effect of Eu upon the light-sensitive properties of Cu in this iodide, with joint activation, was reflected by impurity-induced perturbations of the crystal lattice.

V.D.Bondar, A.S.Grudzinskii, I.M.Zaritskii, S.P.Kolesnik: Fizika Tverdogo Tela, 1995, 37[1], 103-8 (Physics of the Solid State, 1995, 37[1], 53-6)