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The BaFe0.9Sn0.1O3-BaCo0.02ⅡCo0.04ⅢBi0.94O3 com-posite thick films were prepared by screen printing.X-ray dif-fraction(XRD)analysis confirms that the composite films are still composed of BaCo0.02ⅡCo0.04ⅢBi0.94O3 and BaFe0.9Sn0.1O3 phases.For the prepared BaFe0.9Sn0.1O3-BaCo0.02ⅡCo0.04ⅢBi0.94O3 composite thick films,a linear relationship between the logarithmic resistivity and the reciprocal of the absolute temperature is observed,indicating an excellent NTC thermistor characteristic.The values of resistivity at 25 ℃,thermistor constant and activation energy,decreasing with BaCo0.02ⅡCo0.04ⅢBi0.94O3 content increasing,are in the range of 8.9-92,990 Ω·cm,1,126-3,777 K and 0.097-0.325 eV,respectively.Imped-ance analysis shows that at higher BaCo0.02ⅡCo0.04ⅢBi0.94O3 content,the electrical properties of the composite films are mainly attributed to the contribution of grains and grain boundaries.With the gradual decrease of BaCo0.02Ⅱ-Co0.04ⅢBi0.94O3 content,the grain boundaries affect strongly the electrical properties of the composite films.