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大量的实验和理论分析表明:铁电体(包括块体和薄膜材料)都具有一个与体内性质不同的表面层.表面层的存在对铁电体的性质有显著的影响,如介电常数峰值降低,Curie温度偏移,相变点以上仍能观察到热释电效应等.表面层对铁电薄膜性质的影响更加显著,如单晶钛酸钡薄膜的相变表现出弥散特性、介电常数偏低、矫顽场强偏大等.用掠射角X射线衍射法(Glancing angle X-ray diffraction)(GAXRD)可以分析材料浅表层的结构特征,以区分表层与体内的结构差异.
A large number of experimental and theoretical analyzes show that the ferroelectrics (including bulk and thin film materials) have a surface layer with different properties in vivo.The existence of surface layer has a significant impact on the properties of ferroelectrics, such as peak dielectric constant Decrease, Curie temperature shift, the pyroelectric effect can still be observed above the phase transition point, etc. The effect of the surface layer on the properties of the ferroelectric thin film is even more remarkable. For example, the phase transition of a single crystal barium titanate film shows a dispersion characteristic, Low constant, high coercive field strength, etc. Glancing angle X-ray diffraction (GAXRD) can be used to analyze the structural features of the superficial layers of the material to distinguish the structural differences between the superficial and the in vivo structures.