Observation of paramagnetic centers in sodalite
- A. Accorsi, G. Debron, A. P. Legrand, R. Maury
Samples of natural sodalite subjected to various types of radiation and heat treatments have been studied by the techniques of electron spin resonance, nuclear magnetic resonance, optical absorption spectroscopy, ionic thermal currents and electrical conductivity. Several color centers were detected and characterized. One of them attributed to interstitial oxygen near aluminum or silicon ions is detected by the electron spin resonance and optical measurements. The variable temperature data exhibit a rapid decay process followed by a slow decay, and these two processes are believed to arise from the presence of two types of interstitial oxygen sites. Two groups of thirteen line hyperfine patterns were observed which depend on the thermal treatment of the sample before irradiation. One group has a hyperfine coupling constant of 3.5 G and the other, with a coupling constant of 32.0 G is attributed to an unpaired electron at the chlorine vacancy site. We have also observed two bands of dielectric relaxation at 20 and 50 K by means of ionic thermal currents and we report the temperature dependence of the DC electric conductivitv.