Study on the dielectric properties of Ag doped ZnO by “Universal Power Law”

It was found that the dependence of the breakdown field E1mA and the activation energy, on Ag content are similar to that of the exponent of alphalf in low frequency region and alphahf in high frequency region on Ag content, which is a novel result in the research of varistor materials. By means of normalization of conductivity, it was found that samples with different Ag contents show similar mechanism of dielectric loss, which is suggested as the relaxation process of electron in deep level traps. The relation of ac conductivity of samples and scaling frequency shows a deviation from the master curve at high frequencies, which is due to different distribution of local energy barriers and the dynamics of mobile carriers. The results can be fully understood by means of ldquoUniversal Power Law(UPL)rdquo.