Structure and Electrical Properties of Na0.5Bi0.5TiO3 Epitaxial Films with (110) Orientation

Abstract

Pt/Na 0.5 Bi 0.5 TiO 3 /La 0.5 Sr 0.5 CoO 3 (Pt/NBT/LSCO) ferroelectric capacitors were fabricated on (110) SrTiO 3 substrate. Both NBT and LSCO films were epitaxially grown on the (110) SrTiO 3 substrate. It was found that the leakage current density of the Pt/NBT/LSCO capacitor is favorable to ohmic conduction behavior when the applied electric fields are lower than 60 kV/cm, and bulk-limited space charge-limited conduction takes place when the applied electric fields are higher than 60 kV/cm. The Pt/NBT/LSCO capacitor possesses good fatigue resistance and retention, as well as ferroelectric properties with P r = 35 µC/cm 2 . The ferroelectric properties of the Pt/NBT/LSCO capacitor can be modulated by ultraviolet light. The effective polarization, ∆P, was reduced and the maximum polarization P max was increased for the Pt/NBT/LSCO capacitor when under ultraviolet light, which can be attributed to the increased leakage current density and non-reversible polarization Pˆcaused by the photo-generated carriers.

High performance, electroforming-free, thin film memristors using ionic Na0.5Bi0.5TiO3

“…The 600 1C (the lowest growth temperature in this work) films show the highest ON/OFF ratio with the best device uniformity. The minimum growth temperature of 600 1C that we tried in our work is within the optimum growth temperature (600-650 1C) reported in many works for PLD growth of NBT films 48,61,62 (although one study reported a substrate temperature of 550 1C, where they used a lower oxygen pressure during deposition 36 ).…”

“…Furthermore, NBT has potential industrial interest as it can be sputtered at relatively low temperatures. 36 However, while a report in NBT has shown ferroelectric-polarization-controlled RS with 10 3 ON/OFF ratio, 45 V o controlled RS has not been demonstrated.…”

“…32 Also, NBT can be grown with good crystallinity at relatively low temperatures compared with other perovskites. 36 While the RS properties of ionic conductors have been studied before, the performance has not been optimum, i.e. they require high-voltage electroforming (410 V), filaments or high SET voltages (45 V).…”

Progress on Emerging Ferroelectric Materials for Energy Harvesting, Storage and Conversion

“…It has been known that the pure NBT ceramics have a square‐shape P‐E hysteresis loop [ 131 ] with P max ≈ 38 μC cm −2 , which can be doubled when grown into thin films. [ 142 ] By means of chemical modification, for example, dilute Mn doping, Yang et al., reported that the P max and E B can be increased to 113 μC cm −2 and 2.3 MV cm −1 in Mn:NBT‐BT‐BiFeO 3 (Mn:NBT‐BT‐BFO) thin films. [ 143 ] This gives rise to a very high recoverable energy density ( U e = 81.9 J cm −3 ) with η at a value of 64.4%.…”

Synthesis and Characterization of Ferroelectrics

“…Two papers are dedicated to thin-film capacitor applications. The results on structure and electrical properties of lead-free Na 0.5 Bi 0.5 TiO 3 based epitaxial films are reported by Song et al [6]. Pt/Na 0.5 Bi 0.5 TiO 3 /La 0.5 Sr 0.5 CoO 3 (Pt/NBT/LSCO) was fabricated on a (110) SrTiO 3 substrate.…”