The origin of weak coupling between polar clusters in Ta2O5-doped 0.94Bi0.5Na0.5TiO3-0.06BaTiO3Xiafeng He, Shuo Zhou, Zhi Yuan, Yunhua Li, Zhencheng Lan, Kaiyuan Chen, Feifei Han, Xiuyun Lei and Laijun LiuEPL, 129 3 (2020) 37004DOI: https://doi.org/10.1209/0295-5075/129/37004