Study the role of oxygen vacancies and Mn oxidation states in nonstoichiometric CaMnO3-δ perovskite nanoparticles

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS Journal of Sol-Gel Science and Technology Pub Date : 2025-01-04 DOI:10.1007/s10971-024-06632-1

E. K. Abdel-Khalek, E. A. Mohamed, Yasser A. M. Ismail

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Abstract

In this work, the low cost and eco-friendly CaMnO_3-δ perovskite has been prepared by sol-gel method. Rietveld refinement of XRD data indicated that CaMnO_3-δ sample crystallized in orthorhombic structure with space group Pnma. Further characterizations of this sample were performed employing TEM, SAED pattern, HR-TEM, and EDS elemental mapping. These measurements show that the CaMnO_3-δ sample has polycrystalline nature with high degree of crystallinity and all elements are homogeneously distributed. The oxidation states of Mn ions and the presence of oxygen vacancies in this sample were confirmed by XPS analysis. Optical studies revealed that CaMnO_3-δ sample has direct band gap energy (E_g) of 3.63 eV using UV–vis spectroscopy. Asymmetric magnetic hysteresis (M − H) loop in CaMnO_3-δ nanoparticles reveals that the presence of exchange bias phenomenon at room temperature. The present work provides the observation of pseudocapacitive behavior in CaMnO_3-δ nanoparticles. Furthermore, the presence of oxygen vacancies and Mn oxidation states in CaMnO_3-δ sample enhanced the charge storage capability by oxygen intercalation. These results prove that CaMnO_3-δ perovskite is a promising material for magnetic and energy-storage applications.

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来源期刊

Journal of Sol-Gel Science and Technology 工程技术-材料科学：硅酸盐

CiteScore

4.70

自引率

4.00%

发文量

280

审稿时长

2.1 months

期刊介绍： The primary objective of the Journal of Sol-Gel Science and Technology (JSST), the official journal of the International Sol-Gel Society, is to provide an international forum for the dissemination of scientific, technological, and general knowledge about materials processed by chemical nanotechnologies known as the "sol-gel" process. The materials of interest include gels, gel-derived glasses, ceramics in form of nano- and micro-powders, bulk, fibres, thin films and coatings as well as more recent materials such as hybrid organic-inorganic materials and composites. Such materials exhibit a wide range of optical, electronic, magnetic, chemical, environmental, and biomedical properties and functionalities. Methods for producing sol-gel-derived materials and the industrial uses of these materials are also of great interest.