Comments on the compensation effect observed in thermally stimulated depolarization current analysis

Compensation has been reported for the relaxation parameters (the activation energy W and the pre-exponential factor τ0) determined by using the thermal sampling (TS) technique. For the peaks obtained by the thermally stimulated depolarization current (TSDC) measurement, there is a relationship between W, τ0 and the temperature of maximum intensity of the peak Tm that can be employed to deduce a general relationship between W, Tm, the compensation temperature Tc and the compensation time τc. This relationship can be used for a basic analysis of the compensation effect. By numerical simulations, and using parameters similar to those reported for concrete measurements, we show that it is possible to observe a compensation point only if the activation energy is a monotonically increasing power function of temperature of power coefficient between 1 and 2, more precisely, if W increases with temperature stronger than linearly but weaker than quadratically. The actual values of the compensation parameters are determined by the relationship between the activation energy and the temperature. The experimental uncertainties affecting the compensation temperature and the compensation time are significant, and consequently, it is not possible to have a precisely defined compensation point.