In mixed‐valence colossal dielectric materials, the room temperature Maxwell–Wagner response is commonly assigned, in the past literature, to the electrode effect, grain boundary effect, or internal barrier layer capacitor effect. Another underlying phenomenon is brushed aside, and that is of adsorbance of the hydroxyl ions onto the defect centers on the surface of dielectric material. The properties of dielectric materials, especially those having oxygen vacancies, are sensitive to the atmospheric moisture and easily degrade in the humid environment. To study this effect, a series of LaFe_1 − xAl_xO₃ samples (x = 0, 0.1, 0.2, …, 0.8, and 1) are prepared by the sol–gel method, and the effect of humidity sensitivity on their dielectric properties is seen. The samples with greater Fe concentration show distinct humidity‐sensitive properties with both metal electrodes (Pt and Ag) with a very miniscule difference in their measurement values. The effect of hydroxyl ions is further confirmed by the dielectric measurements after the thermal quenching of the samples that verify the adsorbance of water molecules on the surface of dielectric material.

中文翻译：

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湿气吸附对混合价介电材料LaFe1-xAlxO3的影响

在混合价巨大介电材料中，在过去的文献中，室温麦克斯韦-瓦格纳响应通常被分配给电极效应，晶界效应或内部势垒层电容器效应。另一个潜在的现象被抛到一边，那就是羟基离子在电介质材料表面上的缺陷中心上的吸附。介电材料的特性，特别是具有氧空位的介电材料的特性，对大气湿度敏感，在潮湿的环境中容易降解。为了研究这种影响，一系列LaFe _{1 −  x} Al _x O ₃样品（x = 0、0.1、0.2，…，0.8和1）是通过溶胶-凝胶法制备的，并且可以看到湿度敏感性对其介电性能的影响。Fe含量较高的样品对两种金属电极（Pt和Ag）均表现出明显的湿度敏感性，其测量值差异很小。在对样品进行热淬火后，通过电介质测量进一步证实了氢氧根离子的作用，从而验证了水分子在电介质材料表面上的吸附性。