Tuning the local structure of (Sm, Co) Co-doped Al2O3 system for optical band gap and low dielectric loss

IF 5.1 2区材料科学 Q1 MATERIALS SCIENCE, CERAMICS

Ceramics International Pub Date : 2024-09-25 DOI:10.1016/j.ceramint.2024.09.267

Hassan Wahab , Rao Tahir Ali Khan , Mudassar Iqbal

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Abstract

This study is about the qualitative description of the high dielectric constant (>10³) and low dielectric loss in a two co-existing phases. According to earlier beliefs, a material with high dielectric constant will exhibit high dielectric loss. However, this study gives the opposite, where a material with high dielectric constant can exhibit low loss. Herein, we report on the effect of tetrahedral – octahedral interaction in a γ- Al₂O₃ and CoAl₂O₄ biphasic system. Phase identification was carried out using Synchrotron x-ray carrying a wavelength of 0.7 Å. The disorder caused by varying cobalt (Co) concentration results in a two co-existing phase system with varying local polarizability due to mixing of cations in a host matrix. In addition, a decreasing trend in the band gap energy has been observed for both the phases as a function of increasing Co concentration, which is attributed to the intra-gap localized density of states determined from the UV–Vis diffuse reflectance spectroscopy (DRS).

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调整（Sm, Co）共掺杂 Al2O3 系统的局部结构以实现光带隙和低介电损耗

本研究是关于高介电常数（>103）和低介电损耗两相共存的定性描述。根据以前的观点，高介电常数的材料会表现出高介电损耗。然而，这项研究却给出了相反的结论，即高介电常数的材料可以表现出低介电损耗。在此，我们报告了γ- Al2O3 和 CoAl2O4 双相体系中四面体-八面体相互作用的影响。钴（Co）浓度变化引起的无序导致了两个共存相体系，由于阳离子在主基体中的混合，其局部极化率各不相同。此外，随着钴浓度的增加，两种相的带隙能都呈下降趋势，这归因于通过紫外-可见漫反射光谱（DRS）测定的隙内局部态密度。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ceramics International 工程技术-材料科学：硅酸盐

CiteScore

9.40

自引率

15.40%

发文量

4558

审稿时长

25 days

期刊介绍： Ceramics International covers the science of advanced ceramic materials. The journal encourages contributions that demonstrate how an understanding of the basic chemical and physical phenomena may direct materials design and stimulate ideas for new or improved processing techniques, in order to obtain materials with desired structural features and properties. Ceramics International covers oxide and non-oxide ceramics, functional glasses, glass ceramics, amorphous inorganic non-metallic materials (and their combinations with metal and organic materials), in the form of particulates, dense or porous bodies, thin/thick films and laminated, graded and composite structures. Process related topics such as ceramic-ceramic joints or joining ceramics with dissimilar materials, as well as surface finishing and conditioning are also covered. Besides traditional processing techniques, manufacturing routes of interest include innovative procedures benefiting from externally applied stresses, electromagnetic fields and energetic beams, as well as top-down and self-assembly nanotechnology approaches. In addition, the journal welcomes submissions on bio-inspired and bio-enabled materials designs, experimentally validated multi scale modelling and simulation for materials design, and the use of the most advanced chemical and physical characterization techniques of structure, properties and behaviour. Technologically relevant low-dimensional systems are a particular focus of Ceramics International. These include 0, 1 and 2-D nanomaterials (also covering CNTs, graphene and related materials, and diamond-like carbons), their nanocomposites, as well as nano-hybrids and hierarchical multifunctional nanostructures that might integrate molecular, biological and electronic components.