Analysis of complex impedance and electrical conductivity of YCr0.5Mn0.5O3–CaCu3Ti4O12 negative temperature coefficient ceramics

YCr0.5Mn0.5O3(YCM)-CaCu3Ti4O12(CCTO) ceramics were prepared using a solid processing method, and their properties were studied. XRD measurements showed that all prepared ceramics had pure perovskite structures. With increasing YCM content, grain size in ceramics decreased, and the resistivity of materials was found to be very sensitive to grain size and grain size distribution. Moreover, ceramics had NTC characteristics, and values of ρ25, B25/75, and Ea ranged from 2.21 × 106–7.30 × 106 Ω cm, 5797–6300 K, and 0.5390–0.5800 eV, respectively. The presence of heterovalent ion pairs in samples suggested that conduction mechanism may have been related to electron hopping. Impedance spectroscopy results showed that excessive doping with YCM resulted in greater contribution from grains to overall resistance of the material. Temperature-dependent electrical relaxation behavior was dominated by short-range movement of charge carriers.