fig6

Figure 6. Grain size and grain boundary effect of E_b. (A) P-E loops and E_b of BTO with different grain sizes. This figure is quoted with permission from Cai et al.^[81], copyright 2018, John Wiley and Sons; (B) Electric field distribution and (C) breakdown path at the critical breakdown state of samples KNBNTF and KBT. These figures are quoted with permission from Li et al.^[83], copyright 2024, John Wiley and Sons. BTO: BaTiO₃; KNBNTF: KBT-Na_0.5Bi_0.5ZrO₃-Bi_0.85Nd_0.15FeO₃; KBT: K_0.5Bi_0.5TiO₃.