“…While others prefer to attribute it to some extrinsic factors, such as the material microstructure (such as grain size) [7,8], processing conditions (such as sintering temperature and time, cooling rate, etc.) [7][8][9], twin crystals [1], an internal barrier layer capacitance (IBLC) model in which the ceramic is supposed to consist of n-type semiconductive grains and insulating grain or domain boundaries [5,10,11], internal domains inside CCTO grains [11,12], electrode polarization effects [13], a multipole trap charge repositioning model [14,15] and so on. Contact electrode depletion effect [13] and other similar behavior termed Maxwell-Wagner relaxation [16] were also proposed and generally accepted.…”