Negative temperature coefficient thermistor based on Bi3Zn2Sb3O14 ceramic: An oxide semiconductor at high temperature

Bi1.5ZnSb1.5O7 dielectric ceramic with pyrochlore structure was investigated by impedance spectroscopy from 400 to 750 degreesC. Pyrochlore was synthesized by the polymeric precursor method, a chemical synthesis route derived from Pechini's method. The grain or bulk resistance exhibits a sensor temperature characteristic, being a thermistor with a negative temperature coefficient (NTC). Only a single region was identified on the resistance curve investigated. The NTC thermistor characteristic parameter (beta) is equal to 7140 degreesC, in the temperature range investigated. The temperature coefficient of the resistance (alpha) was derived, being equal to -4.46x10(-2) degreesC(-1) at 400 degreesC. The conduction mechanism and relaxation are discussed. (C) 2003 American Institute of Physics.