Entropy regulation in LaNbO_(4)-based fergusonite to implement high-temperature phase transition and promising dielectric properties  

作　　者：Deqin Chen Na Yan Xuefeng Cao Fengrong Li Laijun Liu Qinghua Shen Huanfu Zhou Chunchun Li 

机构地区：[1]Guangxi University Key Laboratory of Non-ferrous Metal Oxide Electronic Functional Materials and Devices,College of Material Science and Engineering,Guilin University of Technology,Guilin 541004,China [2]Guangxi Key Laboratory of Embedded Technology and Intelligent System,Guilin University of Technology,Guilin 541004,China

出　　处：《Journal of Advanced Ceramics》2023年第5期1067-1080,共14页先进陶瓷（英文）

基　　金：Fundamental Research Funds of Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices(No.AFMD-KFJJ-21210);the financial support from the National Natural Science Foundation of China(No.62061011);Guangxi Key Laboratory Fund of Embedded Technology and Intelligent System(No.2020-1-6).

摘　　要：High-entropy effect is a novel design strategy to optimize properties and explore novel materials.In this work,(La_(1/5)Nd_(1/5)Sm_(1/5)Ho_(1/5)Y_(1/5))NbO_(4)(5RNO)high-entropy microwave dielectric ceramics were successfully prepared in the sintering temperature(S.T.)range of 1210–1290℃via a solid-phase reaction route,and medium-entropy(La_(1/3)Nd_(1/3)Sm_(1/3))NbO_(4) and(La_(1/4)Nd_(1/4)Sm_(1/4)Ho_(1/4))NbO_(4)(3RNO and 4RNO)ceramics were compared.The effects of the entropy(S)on crystal structure,phase transition,and dielectric performance were evaluated.The entropy increase yields a significant increase in a phase transition temperature(from monoclinic fergusonite to tetragonal scheelite structure).Optimal microwave dielectric properties were achieved in the high-entropy ceramics(5RNO)at the sintering temperature of 1270℃for 4 h with a relative density of 98.2%and microwave dielectric properties of dielectric permittirity(ε_(r))=19.48,quality factor(Q×f)=47,770 GHz,and resonant frequency temperature coefficient(τ_(f))=–13.50 ppm/℃.This work opens an avenue for the exploration of novel microwave dielectric material and property optimization via entropy engineering.

关 键 词：high-entropy ceramics microwave dielectric property ion disorder FAR-INFRARED 

分 类 号：TQ174.1[化学工程—陶瓷工业]