fig6

Figure 6. EPR spectra of (A) BT, BC4T, and BTC4 ceramics measured at 100 K, and (B) BTC4 ceramic measured at different temperatures; (C)The model of trapping effect by $$ C a_{T i}^{\prime \prime} $$ and $$ V_{T i}^{\prime \prime \prime \prime} $$. EPR: electron paramagnetic resonance.