钬铬共掺铁酸铋薄膜对钛酸铋钠钾铁电薄膜的性能调控

Tailoring the Properties of Potassium Sodium Bismuth Titanate Ferroelectric Thin Film by Holmium/Chromium Co-doping Bismuth Ferrite Films

用溶胶-凝胶法,在Pt/Ti/SiO2/Si(100)衬底上制备了钬铬共掺铁酸铋(BHFCO)-钛酸铋钠钾(NKBT)薄膜,系统研究不同BHFCO掺杂量对(1-x)NKBT-xBHFCO薄膜的微观结构、表面形貌和电学性能的影响.结果表明:680℃退火处理后的(1-x)NKBT-xBHFCO薄膜表面比较均匀、致密,结晶度较好;0.95NKBT-0.05BHFCO薄膜样品的剩余极化值(2Pr)最大(71.3μC/cm^2),矫顽场最小(2Ec=530kV/cm),电滞回线饱和矩形度最好,漏电流最小(2.1×10-6A/cm^2).0.95NKBT-0.05BHFCO薄膜的,相对介电常数最大(约为493),介电损耗最小(约为0.04);薄膜的高温介电温谱表明,所有薄膜的居里温度(Tc)在(450±10)℃.不同厚度薄膜的介电性能表明,铁电薄膜内部的挠曲电效应显著降低了薄膜的最大介电常数值.

(1-x)Na 0.41 K 0.09 Bi 0.5 TiO 3 (NKBT)-x Bi 0.85 Ho 0.15 Fe 0.97 Cr 0.03 O 3 (BHFCO)( x= 0.01,0.03, 0.05, 0.07) thin films were prepared by the sol-gel method, and the effect of BHFCO content on the properties of these thin films were studied systemically. The results show that the incorporation of BHFCO into NKBT does not change the crystal structure of the NKBT obviously. The 0.95NKBT-0.05BHFCO thin film shows the maximum remanent polarization value (2 P r ≈71.3 μC/cm^2 ), the minimum coercive field (2 E c =530 kV/cm) and also shows the best saturation rectangle degree, the least leakage current density (2.1×10 -6 A/cm^2 ). Additionally, this binary system film is of the maximum dielectric constant (about 493) and the minimum dielectric loss (about 0.04). In addition, it is found that the Curie temperature of these films are between 440 ℃ and 460 ℃ by testing the dielectric temperature spectra. The effect of the flexoelectric polarization on the dielectric properties of these ferroelectric thin films is analyzed under different film thickness, showing that the flexoelectric effect plays an important role in reduction of the maximum dielectric constant of these ferroelectric thin films.