Dielectric, mechanical and optical properties of orthorhombic KNbO-3
Dielectric, mechanical and optical properties of orthorhombic KNbO-3
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斜方晶系 KNbO-3 的介电、机械和光学性能
DOI：
10.3929/ethz-a-000277526
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发表时间：
1973
期刊：
影响因子：
0.8
通讯作者：
E. Wiesendanger
中科院分区：
文献类型：
--
作者：
E. Wiesendanger
测量了单畴KNbO3的介电常数、压电常数和弹性常数，并估计了电光r系数。结果可以彻底验证德文郡的正交相理论。在介电和压电性能上发现了良好的一致性，而拟合弹性行为需要包含自发应变耦合刚度项。箝位介电常数和弹性刚度的温度依赖性表明了压电耦合对低温相变的重要性。吸收测量显示近各向同性极化诱导的200 meV的带边偏移。在10 eV的偏振紫外反射光谱中观察到较大的各向异性。铁电kbo3的反射率与立方kta3的电反射率的比较进一步证明了氧-八面体化合物中电光效应的统一性。由Kramers-Kronig法得到的e " -光谱的差异…
Dielectric, piezoelectric and elastic constants have been measured in single domain KNbO3, and electrooptic r-coefficients are estimated. Results allow a thorough verification of Devonshire's theory for the orthorhornbic phase. Good agreement is found for the dielectric and piezoelectric properties whereas fitting the elastic behaviour requires inclusion of terms coupling stiffness to spontaneous strain. The temperature dependence of clamped dielectric constants and elastic stiffness points to the importance of piezoelectric coupling for the low temperature phase transitions. Absorption measurements reveal a nearly isotropic polarization-induced band edge shift of 200 meV. Large anisotropy is observed in the polarized UV reflectance spectra measured up to 10 eV. Comparison of reflectivity in ferroelectric KNbO3 with electroreflectance in cubic KTaO3 gives further evidence for the unified nature of electro-optic effects in oxygen-octahedra compounds. Differences in e''-spectra derived from Kramers-Kronig a...