沿a/b轴择优取向Bi_4Ti_3O_(12)铁电薄膜的回线动力学标度

Scaling on Dynamic Hysteresis of a/b-axes Oriented Bi_4Ti_3O_(12) Thin Films

测量了在Pt／Ti／SiO2／Si上生长的36％a／b轴择优取向Bi4Ti3O12铁电薄膜的电滞回线，并研究了薄膜的回线动力学标度。外加电场频率的变化范围0．4～10kHz，电场幅值的变化范围653～1045kV·cm^-1。在外电场频率一定时，该Bi4Ti3O12薄膜的回线面积随外电场幅值的增大而增大。当外电场幅值固定时，回线面积随外电场频率的上升先增加后减小。当f=1kHz时，回线面积最大。由此可知，该Bi4Ti3O12薄膜中畴翻转的特征时间约1ms。在外电场频率低于1kHz时，回线面积〈A〉∝f^-0.02883E0；在1kHz以上高频段有标度关系〈A〉∝f^-0.05388E0。

Ferroelectric hysteresis of Bi4Ti3O12 thin films with 36% a/b-axes oriented grains grown on Pt/Ti/SiO2/Si substrates was measured and the scaling behavior of dynamic hysteresis was investigated. The electric field frequency f ranged from 0.4 to 10 kHz and the amplitude （E0） range was 653-1 045 kV · cm^-1. The hysteresis area 〈A〉 increases with E0 at fixed f. The hysteresis area 〈A〉 firstly grows and then decreases with increasing f at fixed E0. The largest hysteresis area 〈A〉 was obtained at 1 kHz. So the characteristic time of domain reversal is 1 ms. The scaling relations of hysteresis area 〈A〉 against frequency f and field amplitude Eo for the loops of a/b-axes oriented Bi4Ti3O12 thin films are 〈A〈∝f^ -0.02383 E0 when f is lower than 1 kHz and 〈A〉∝f^-0.05388E0 when f is higher than 1 kHz.