BaTiO_3基PTCR陶瓷中Bi_2O_3蒸汽掺杂和Mn的协同作用

Coordinated function of Bi_2O_3 vapor dopant and Mn acceptor in BaTiO_3-based PTCR ceramics

ＢａＴｉＯ３基陶瓷材料的ＰＴＣＲ效应与施受主掺杂密切相关。通过Ｂｉ２Ｏ３、Ｓｂ２Ｏ３等蒸汽掺杂，材料的ＰＴＣＲ效应可以得到提高。然而，蒸汽掺杂之后，ＰＴＣＲ效应提高的幅度在含受主Ｍｎ的材料中比纯施主掺杂的材料中要大得多。这与Ｂｉ２Ｏ３蒸汽掺杂和Ｍｎ的协同作用密切相关。这种协同作用可能进一步形成三价Ｍｎ或中性钡缺位相关的更为稳定的复合缺陷，从而增大了电子捕获中心的浓度，使材料ＰＴＣＲ效应大幅度提高。

The PTCR effect of BaTiO3-based semiconducting ceramics was allied to donor and acceptor impurities. It could be enhanced by some vapor dopants such as Bi2O3 etc. However, the enhancement of the sample doped with Mn is much greater than that of the sample doped by pure donor. The result is associated with the coordinated function of Bi2O3 vapor dopant and Mn acceptor at grain boundary in BaTiO3 ceramics. More stable composite defects could be formed in the sample doped by both Bi2O3 vapor and Mn acceptor, and they were related to trivalent Mn ion and neutral barium vacancy. Therefore, the concentration of free electron capture center is increased, and the PTCR effect could be enhanced greatly.