Structure and electrical properties of Bi0.5Ba0.5FeO3-Y2O3 composite NTC ceramics

Publication date: October 2019Source: Materials Science and Engineering: B, Volume 249Author(s): Peng Fu, Guangtan Miao, Ming Yin, Wei Li, Jigong Hao, Guorong Li, Chuming WangAbstract(1 − x) Bi0.5Ba0.5FeO3 (BBF)-xY2O3 negative temperature coefficient (NTC) ceramics were prepared by solid-state reaction method. With increasing Y2O3 contents, the grain sizes of the samples increase. All (1 − x) BBF-xY2O3 ceramics have the typical NTC effect. The conductive mechanism of BBF based ceramics is largely the electron hopping. The thermistor constants B25/75 of the (1 − x) BBF-xY2O3 ceramics keep the lager values in the range of 6441 to 7611 K. The resistivity at 25 °C decreases from 7.82 × 107 Ω cm for the pure BBF ceramic to 106 Ω cm magnitudes for the 0.80 BBF-0.20Y2O3 ceramic. The activation energy Ea of samples is in the range of 0.5003–0.5529 eV. The impedance analysis indicates that the grain boundary resistances are higher than intragrain resistances in BBF based ceramics. All samples have the single relaxation process, and the relaxation phenomena are attributed to hopping of oxygen vacancies.
Source: Materials Science and Engineering: B - Category: Materials Science Source Type: research