Entropy regulation in LaNbO4-based fergusonite to implement high-temperature phase transition and promising dielectric properties

• DOI: 10.26599/jac.2023.9220739
• Publication Date: 2023-03-02T03:06:31Z
• Authors: Deqin Chen; Na Yan; Xuefeng Cao; Fengrong Li; Laijun Liu; Qinghua Shen; Huanfu Zhou; Chunchun Li
• Keywords: Tetragonal crystal system; Temperature coefficient

High-entropy effect is a novel design strategy to optimize properties and explore materials. In this work, (La_1/5Nd_1/5Sm_1/5Ho_1/5Y_1/5)NbO₄ (5RNO) high-entropy microwave dielectric ceramics were successfully prepared in the sintering temperature (S.T.) range of 1210–1290 ℃ via solid-phase reaction route, medium-entropy (La_1/3Nd_1/3Sm_1/3)NbO₄ (La_1/4Nd_1/4Sm_1/4Ho_1/4)NbO₄ (3RNO 4RNO) compared. The effects entropy (<i>S</i>) on crystal structure, phase transition, performance evaluated. increase yields significant transition (from monoclinic fergusonite tetragonal scheelite structure). Optimal achieved at 1270 for 4 h with relative density 98.2% permittirity (<i>ε</i>_r) = 19.48, quality factor (<i>Q</i>×<i>f</i>) 47,770 GHz, resonant frequency coefficient (<i>τ</i>_f) –13.50 ppm/℃. This work opens an avenue exploration material property optimization engineering.