Electrical transport in ferroelectric Pb[(Fe_1/3Sb_2/3)_xTi_yZr_z]O₃ ceramics

Abstract

In this article, the studies of the polarization currents and current–voltage characteristics (J–V) are presented. The measurements of the J–V in low and high temperatures as well as at low and high voltages have permitted to recognize certain details of local energy levels in forbidden gap. It has been possible to calculate energy trap levels and their concentration. Calculated trap energy and concentration, under the condition of single trap energy levels, are equal: E _t = 0.55 eV, N _t = 2.97 · 10²³ m⁻³ for the sample y = 0.44 and E _t = 0.59 eV, N _t = 1.5 · 10²³ m⁻³ for the sample y = 0.47. Knowing the J–V characteristic and the Seebeck coefficient the carriers concentration and their mobility can also be calculated. The carriers concentration and their mobility are equal: n = 3.8 · 10¹⁸ m⁻³, µ = 1.4 · 10⁻¹² m² V⁻¹ · s⁻¹ for sample y = 0.44 and n = 6.9 · 10¹⁶ m⁻³, µ = 1.3·10⁻¹¹ m² V⁻¹ · s⁻¹ for the sample y = 0.47.

Keywords:

• ferroelectrics
• space-charge-limited currents
• PZT-PFS ceramics
• polarization currents
• J–V characteristics
• Seebeck coefficient

Acknowledgement

The authors would like to thank Prof Kristian Roleder for many useful and stimulating discussions.