Preparation and electrical characterization of a new linear negative temperature coefficient (1−x)BaSn0.96Sb0.04O3–xCoFe0.5Co1.5O4 composite ceramics

• The BaSn0.96Sb0.04O3–CoFe0.5Co1.5O4 composite ceramics were successfully prepared.
• As CoFe0.5Co1.5O4 amount increases, linear ceramics are more dense and low porous.
• The ρ-T relationships of ceramics present good linear characteristic at 0–200 °C.

(1−x)BaSn0.96Sb0.04O3–xCoFe0.5Co1.5O4 (x=0.1, 0.3, 0.5, 0.7 and 0.9) composite ceramics had been fabricated through conventional solid-state method. The X-ray diffraction analysis indicated that the composite ceramics consisted of two phases: a perovskite BaSn0.96Sb0.04O3 phase and a cubic spinel CoFe0.5Co1.5O4 phase. The composite ceramics were more dense and lower porosity with increasing the CoFe0.5Co1.5O4 content by SEM. The obtained ρ25 and B25/50 constants and activation energy of the composite ceramics were in the range of 1.61×105–1.06×106 Ω cm, 1048–8458 K and 0.09–0.729 eV, respectively. In particular, their relationship between R and T which differed from normal NTC displayed a good linear characteristic at 0–200 °C. It could be used expediently in digital instrument and precision measurement.