Ba[(Mg1/3Nb2/3)1-xHfx]O3 (BMNH, x = 0.05, 0.1, 0.15, 0.2) solid solutions were prepared via the solid-state reaction method. The effect of BaHfO3 on the crystal structure, microwave dielectric performance and defect relaxation behavior of Ba(Mg1/3Nb2/3)O3 (BMN) were studied. BaHfO3 additions degraded the sintering activity of BMN powder, requiring a high sintering temperature (Ts) ~ 1650 °C; but it could be effectively improved by a prolonged sintering process at a lower Ts of 1600 °C. The well-sintered BMNH ceramics (1600 °C for 30 h) possessed a high densification > 96%, and exhibited cubic perovskite structures without 1:2 cation ordering. Once doped with Hf, the low-temperature relaxation in dielectric spectroscopy and thermally stimulated depolarization current (TSDC) for pure BMN disappeared, further indicating such relaxation is related to cation-ordered structure. Oxygen vacancies, namely showing in-grain and across-grain-boundary relaxation of Vo -related defects, were the main defect types in BMNH. The concentrations of in-grain Vo decreased as x increased, which is beneficial for BMNH to maintain high Q×f values of 69 400 ~73 000 GHz. Accompanied with a high er of 33.27 ~ 33.59 and a low τf of +13.6 ~ +20.7 ppm/°C, these materials have a good potential for applications in microwave components and devices. This article is protected by copyright. All rights reserved.

中文翻译：

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Ba[(Mg1/3 Nb2/3 )1- x Hf x ]O3固溶体的晶体结构、缺陷弛豫和微波介电性能

Ba[(Mg1/3Nb2/3)1-xHfx]O3 (BMNH, x = 0.05, 0.1, 0.15, 0.2)固溶体通过固相反应法制备。研究了 BaHfO3 对 Ba(Mg1/3Nb2/3)O3 (BMN) 晶体结构、微波介电性能和缺陷弛豫行为的影响。BaHfO3 添加降低了 BMN 粉末的烧结活性，需要较高的烧结温度 (Ts) ~ 1650 °C；但它可以通过在 1600 °C 的较低 Ts 下延长烧结过程来有效改善。烧结良好的 BMNH 陶瓷（1600 °C 30 小时）具有 > 96% 的高致密化，并表现出立方钙钛矿结构，没有 1:2 的阳离子排序。一旦掺杂了 Hf，纯 BMN 的介电光谱和热刺激去极化电流 (TSDC) 中的低温弛豫消失了，进一步表明这种弛豫与阳离子有序结构有关。氧空位，即显示 Vo 相关缺陷的晶粒内和跨晶粒边界弛豫，是 BMNH 中的主要缺陷类型。随着 x 的增加，晶粒内 Vo 的浓度降低，这有利于 BMNH 保持 69 400 ~73 000 GHz 的高 Q×f 值。伴随着 33.27 ~ 33.59 的较高 er 和 +13.6 ~ +20.7 ppm/°C 的低 τf，这些材料在微波元件和设备中具有良好的应用潜力。本文受版权保护。版权所有。这有利于 BMNH 保持 69 400 ~73 000 GHz 的高 Q×f 值。伴随着 33.27 ~ 33.59 的较高 er 和 +13.6 ~ +20.7 ppm/°C 的低 τf，这些材料在微波元件和设备中具有良好的应用潜力。本文受版权保护。版权所有。这有利于 BMNH 保持 69 400 ~73 000 GHz 的高 Q×f 值。伴随着 33.27 ~ 33.59 的较高 er 和 +13.6 ~ +20.7 ppm/°C 的低 τf，这些材料在微波元件和设备中具有良好的应用潜力。本文受版权保护。版权所有。