A technique was presented for the study of paramagnetic defects, in insulators or semiconductors, which acted as positron traps. The spin polarization of the paramagnetic electrons of such centers could be determined by investigating the annihilation of spin-polarized positrons, using Doppler broadening or positron lifetime measurements. The technique was demonstrated by measuring the temperature dependence of the polarization of the paramagnetic electrons of F- centers in KCl in a high magnetic field (4.5T).

C.Deckers, J.Ehmann, H.Greif, F.Keuser, W.Knichel, U.Lauff, K.Maier, A.Siegle, M.Tongbhoyai: Journal de Physique III, 1995, 5[C1], 81-6