用扫描压电显微术观察不同掺杂PZT薄膜的铁电畴分布

Investigation of domain distribution using scanning piezoelectric microscopy for PZT thin films with different dopants

我们用扫描压电显微术 ,观察了未掺杂和掺La、Eu的PZT的铁电畴分布 ,结果表明 :在自发极化下 ,用溶胶-凝胶法得到的PZT ,(Pb0 93La0 0 7) (Ti0 6 Zr0 4)O3,(Pb0 95Eu0 0 5) (Zr0 52 Ti0 48)O3和 (Pb0 9Eu0 1 ) (Zr0 52 Ti0 48)O3的表面铁电畴呈现较大的不同 ,掺La和掺Eu的样品均比未掺杂的有较大的自发极化。含Eu为 5 %时自发极化强度最高 ,且大部分畴界位置与晶界接近。通过改变加在探针上交变电压的幅值 ,观察铁电畴衬度的变化 ,可以看到 ,当交变电压升高时 ,某些畴变得不稳定 ,极化方向不同于自发极化 ,而衬度随交变电压线性增加 ,表明该区域晶粒在垂直方向贯通膜面 ,矫顽力高于外电场 。

The distribution of ferroelectric domain of PZT thin film and La, Eu doped PZT thin films were investigated using scanning piezoelectric microscopy. The experimental results showed that the surface ferroelectric domains of sol-gel derived PZT,(Pb 0.93La 0.07)(Ti 0.6Zr 0.4)O 3, (Pb 0.95Eu 0.05)(Zr 0.52Ti 0.48)O 3 and (Pb 0.9Eu 0.1)(Zr 0.52Ti 0.48)O 3 had different structure at spontaneous polarization. The thin film with 5% Eu dopant had the highest spontaneous polarization, and the boundaries of most domains were the same to the grain boundary. The variation of the contrast of domain was observed by changing the amplitude of alternate voltage applied to the cantilever. It showed that some domains were getting unstable while higher voltage was applied, and their polarized orientations were different to those at spontaneous polarization. The linear increasing of the contrast at some locations means that the grain was penetrative across the depth of the thin film, the coersive field was higher than applied field, and the defects were lower for evident loss of piezoelectricity at this area.