Low temperature electrical conduction mechanisms in disordered materials with an application to Calcium Strontium Copper Titanate ceramics

Hopping conduction mechanism is studied in Strontium doped Calcium Copper Titanate (CSCTO) ceramics at low temperatures down to 93 K. The method of analyzing the local activation energy is used to identify the variable range hopping (VRH) nature in these ceramics. The frequency dependence of the corresponding localization length of mobile charge carriers is discussed. The electrical conductivity analysis in frequency up to 1 MHz suggests the predominance of the overlapping large polaron tunneling (OLPT) mechanism. The data are analyzed in light of existing theoretical models of VRH and OLPT. •Variable range hopping (VRH) conduction of the Mott type is studied in CCTO.•Mott type VRH down to 100 K is identified by two different methods.•The effect of frequency on Mott-VRH parameters is analyzed.•The OLPT mechanism is analyzed near 1 MHz.