PARAMAGNETIC RESONANCE OF ASSOCIATED IMPURITIES IN CADMIUM SULPHIDE

Paramagnetic resonance spectra attributed to three Fe3+:Cu associated centres A, B and C have been studied at 77°K in cadmium sulphide single crystals. The results are explained with an orthorhombic spin Hamiltonian H = gβH. S + D{Sz2 - fraction one-third S(S+1)} + E(Sx2 - Sy2) with S = fraction five-twos,|E| <|D| and|D| > hv. The x and y axes of centres A and B lie in the 112, macron0 plane and the x axes for A and B make angles of 21·0°and 29·2°with the c axis respectively. The centre C is less well defined. The parameters D and E, taking g = 2·01, are estimated to within 5% for A as D = -0·537 cm-1, E = 0·116 cm-1 and for B as D = -0·372 cm-1, E = 0·0845 cm-1. The resonance is not photosensitive. The association between the Fe and Cu is a possible explanation of the killer action of Fe on the CdS:Cu luminescence.