Defect and electrical conduction in Mn-doped CaCu3-xMnxTi4O12 negative temperature coefficient ceramics

• The defect and electrical conduction in ceramics have been successfully investigated.
• Linear electrical behaviors can be enhanced by the substitution of Mn ions.
• The defect may result from the cation non-stoichiometry at the low temperature.
• The defect may result from the oxygen vacancy at the high temperature.

The defect and electrical conduction in Mn-doped CaCu3-xMnxTi4O12 (0 ≤ x ≤ 1) negative temperature coefficient (NTC) ceramics were successfully investigated by using defect chemistry theory in combination with X-ray photoelectron spectroscopy (XPS) analysis. An approximate linear relationship between the natural logarithm of the resistivity and the reciprocal temperature for Mn-doped samples was observed in comparison to CaCu3Ti4O12, and these linear electrical behaviors were extremely enhanced with increasing Mn content. As the Mn concentration increased, Ea25-500◦C decreased and Ea500-800◦C increased at first and then slightly decreased. The defect in these ceramics may mainly result from the cation non-stoichiometry in the temperature range from ambient to 500 °C and oxygen vacancy after 500 °C.