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Effect of Humidity Adsorption on Mixed Valence Dielectric Material LaFe 1− x Al x O 3
Author(s) -
Ahmed Rida,
Rehman Sajid ur,
Si Renjun,
Wang Chunchang
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000342
Subject(s) - dielectric , materials science , humidity , analytical chemistry (journal) , valence (chemistry) , adsorption , grain boundary , ion , moisture , electrode , chemistry , composite material , thermodynamics , microstructure , chromatography , organic chemistry , physics , optoelectronics
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 − x Al x O 3 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.