Electrical properties of thick film NTC thermistors based on SrFe0.9Sn0.1O3−δ

The thick film negative temperature coefficient (NTC) thermistors based on SrFe0.9Sn0.1O3–δ were fabricated on alumina substrate by screen-printed technique. The fired thick films were characterized by X-ray diffraction, scanning electron microscopy and complex impedance analysis. The thick film samples showed compact and homogeneous microstructure. Depending on the thick film composition, the values of the resistivity at 25 °C, thermistor constant and activation energy are in the range of 65.5–4860 Ω cm, 2611–3558 K and 0.229–0.312 eV, respectively. Impedance spectroscopy analysis showed both grain and grain boundary resistances decrease with a rise in temperature for the composition SrFe0.9Sn0.1O3–δ with the glass phases of 5 mol% BaBiO3 and 5 mol% CuO. The conduction mechanism and relaxation behavior were also discussed.

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