On the influence of strain on ion transport: microstructure and ionic conductivity of nanoscale YSZ|Sc2O3 multilayers.
On the influence of strain on ion transport: microstructure and ionic conductivity of nanoscale YSZ|Sc2O3 multilayers.
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DOI：
10.1039/c0cp01018a
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
N. Schichtel;C. Korte;D. Hesse;N. Zakharov;B. Butz;D. Gerthsen;J. Janek
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文献类型：
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作者：
N. Schichtel;C. Korte;D. Hesse;N. Zakharov;B. Butz;D. Gerthsen;J. Janek
采用脉冲激光沉积法(PLD)在(0001)蓝宝石衬底上制备了(YSZ|Sc2O3)×n型多层膜样品，膜厚在8 nm(n=100)~250 nm(n=5)之间。用X射线衍射仪(XRD)、扫描电子显微镜(HRSEM)和透射电子显微镜(TEM/HRTEM)、选区电子衍射(SAED)和电子能量损失谱(EELS)对样品进行了表征。多晶层呈柱状组织，这是所用制备技术的典型特征。结果表明：(0001)Al_2O_3-‖(111)-Sc_2O_3-‖(111)Y_2O_3稳定氧化锆(YSZ)和氧化钪(Sc_2O_3)与衬底之间只有一种轴向取向关系。SAED、X射线衍射极图测量和高分辨电子显微镜的快速傅立叶变换(FFT)表明，晶体的方位向旋转也存在择优取向关系。YSZ、Sc2O_3与衬底的界面比较尖锐，不存在扩散过渡区。位错似乎没有按规则排列。随着界面密度的增加(多层膜中各层较薄)，多层膜的导电性降低。我们将其与YSZ-Sc2O3界面上存在的负名义失配(YSZ相界面处的压应力)相关联。这一观察结果与之前调查的YSZ|Y2O3(A.Peter等人，Phys.化学。化学。Phys，2008，10,4623)，其中在YSZ相界处存在拉伸失配应变，导致电导率增加。
Multilayer samples of the type (YSZ|Sc2O3) × n with layer thicknesses between 8 nm (n=100) and 250 nm (n=5) were prepared on (0001) sapphire substrates by pulsed laser deposition (PLD). The samples were characterised using X-ray diffraction (XRD), scanning electron microscopy (HRSEM) and transmission electron microscopy (TEM/HRTEM, SAED (selected-area electron diffraction) and quantitative EELS (electron energy-loss spectroscopy)). The polycrystalline layers show a columnar microstructure, which is typical for the used preparation technique. The layers are highly textured and only one axial orientation relation is found between yttria-stabilised zirconia (YSZ), scandium oxide and the substrate: (0001) Al2O3‖(111) Sc2O3‖(111) YSZ. A preferred orientation relationship also exists for the azimuthal rotation of the crystallites, which was demonstrated by SAED, XRD pole figure measurements and fast Fourier transformation (FFT) of HRTEM micrographs. The interfaces between YSZ, Sc2O3 and the substrate are sharp and do not contain diffuse transition regions. Dislocations appear not to be arranged in regular arrays. With increasing interface density (thinner individual layers in the multilayer), the conductivity of the multilayers decreases. We relate this to the negative nominal misfit present at the YSZ|Sc2O3 interfaces (compressive stress in YSZ at the phase boundaries). This observation agrees well with the previously investigated case of YSZ|Y2O3 (A. Peters et al., Phys. Chem. Chem. Phys., 2008, 10, 4623), where tensile misfit strain was present in YSZ at the phase boundaries, leading to a conductivity increase.