It was recalled that electron paramagnetic resonance and dielectric relaxation were 2 powerful techniques for the study of dipolar defects in insulating materials. Thus, electron paramagnetic resonance provided information on the structure of the defects while dielectric relaxation could reveal their relaxation kinetics. When used separately, it was difficult to correlate the information which these techniques provided. However, it was proposed here that, by exploiting the Stark effect, an experiment could be performed by combining these 2 techniques so that relating defect relaxation to the defect structure became trivial. Such an experiment could be performed in 2 ways. Firstly, a so-called electron paramagnetic resonance mode could be used in which the temperature and frequency were kept constant and the magnetic field was varied. Here, for every electron paramagnetic resonance line with appreciable Stark splitting, a real component appeared in the lock-in signal. An imaginary signal appeared only for those electron paramagnetic resonance lines which arose from the defect of interest. This could aid in clarifying an otherwise very complex electron paramagnetic resonance spectrum by revealing which peaks arose from which defect. Alternatively, experiments could be performed in so-called dielectric relaxation mode, in which the magnetic field was fixed on a chosen electron paramagnetic resonance line and either the temperature or the frequency was varied. Thus, the relaxation parameters could be measured for a given defect.

F.Charnock, H.Shields, G.E.Matthews: Materials Science Forum, 1997, 239-241, 353-6