Electrical properties and temperature sensitivity of Mo-modified CuFe₂O₄ceramics

Mo-modified CuFe2O4 ceramics, CuFe2−xMoxO4 (x = 0, 0.03, 0.05, 0.06 and 0.07), were synthesized by the wet chemical process followed by the traditional ceramic sintering process operating at 1000 °C in the air. The phase component and electrical properties of the ceramics were investigated. The Mo-doped CuFe2O4 ceramics have the cubic spinel phase, and show a typical characteristic of negative temperature coefficient (NTC) of resistivity in the temperature range from 25 to 250 °C. The thermal-sensitivity constants (B25/85) of the ceramics can be adjusted from 2971 to 4180 K by substitution of Mo-ions into the ceramics. The analysis of complex impedance reveals that both grain effect and grain-boundary effect contribute to the conductivity and NTC feature of the ceramics. The conduction mechanisms in the ceramics are proposed to be the polaron hopping conduction model inside the grains and the thermally activated electron transport at the grain boundaries.