The electrical properties of the irradiated dielectric oxides

Full text: In this work we studied the pre-dose effect of ionizing radiation in crystalline phase of ceramic dielectrics materials. Take into account, that a crystalline phase of many ceramic materials is appear the crystalline oxides -corundum and quartz, we investigated effect of different ionizing radiation doses of Co60 course on their electrical properties. This paper discusses effect of the radiation on the electric conductivity (σ) of high pure samples of the corundum (I) and quartz (II) cut parallel (no. 1) and normal (no. 2) to the main optical axis. Measurement of the electric conductivity of no. 1 samples (for I, II) at direct current within the temperature interval of 300-670 K before irradiation showed that there are two regions of linear dependence bent at Tb=430 K. The shapes of the σ(T) dependencies for samples no. 1 and no. 2 type are alike. Irradiation to 104 Gy leads to a increase till Tb, above this temperature there are no noticeable changes after the irradiation in the II samples, for the I samples - is decrease σ. Activation energies E1 and E2 for low- and high-temperature region were calculated for I and II samples. It is shown, that activation energies of conductivity process not many depend from the dose D of irradiation. This was indicated on possibility presentation of the conductivity characters of the crystals. Has been shown the opportunity of describing σ(T) in irradiated quartz samples at high temperature through the analytic equation: σ(T)=A exp{-(Ea+Eb)/k T}, were Ea and Eb - displacement and migrations energy accordingly, A -empirical constancy. Note that the value of (Ea+Eb)=0.83 eV in irradiated samples. It is determined, that value of activation energies for the quartz samples no changed after irradiation. The dose dependencies of the conductivity in this plates was found to be nonmonotonic. For example, on the curve σ(D) in the II samples at D=104 Gy of the maximum was appearance and in the I samples at D=105 Gy of the minimum was appearance. These kinetics of the dependence σ(D) for the temperatures 300-375 K were established. The problems connected with the possible of causes was established of the peculiarities of kinetics in the position of the existence models is discussed an the base of these characteristics analysis for the gamma-irradiated a crystalline phases