材料科学
四方晶系
凝聚态物理
相变
铁电性
电介质
正交晶系
介电常数
居里温度
压力(语言学)
相(物质)
朗道理论
结晶学
晶体结构
化学
铁磁性
物理
哲学
光电子学
有机化学
语言学
作者
Florian H. Schader,Nasser Khakpash,George A. Rossetti,Kyle G. Webber
摘要
The relative permittivity of polycrystalline BaTiO3 was measured from –150 °C to 250 °C at compressive bias stresses up to −500 MPa. Mechanical loading shifted the rhombohedral-orthorhombic, orthorhombic-tetragonal, and tetragonal-cubic phase transition temperatures and produced a pronounced broadening of the dielectric softening in the vicinity of all three transitions. The inter-ferroelectric rhombohedral-orthorhombic and orthorhombic-tetragonal phase transitions were found to be less stress sensitive than the ferroelectric-paraelectric transition occurring between tetragonal and cubic phases at the Curie point. The application of compressive stress resulted in a strong suppression of the relative permittivity, such that at the highest applied stress of −500 MPa, the permittivity in the single phase regions away from the phase transitions was found to display only a weak dependence on temperature between −100 °C and 125 °C. The experimental observations closely followed the predictions of a 2-4-6 Landau polynomial wherein the dielectric stiffness and higher-order dielectric stiffness coefficients are linear functions of uniaxial stress.
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