Generally, the relaxation dynamics can be well explained in terms of Arrhenius law (or sometime the Vogel-Fulcher law), which explains the shift of Z" peak frequencies towards higher frequencies and are seen in most of the materials showing NTCR effect. But for materials showing PTCR effect, the peak shifts downward towards the lower frequencies within the PTCR temperature region. How to explain this downward shift of Z" or M" peak frequency towards lower frequencies with increase in temperature?