New types of multi-component Li_3+xMg_2–2xNb_1-xTi_2xO₆ (0 ≤ x ≤ 1) solid-solution ceramics were designed based on the Li₂TiO₃−Li₃NbO₄−MgO pseudo ternary phase diagram and studied for microwave dielectric applications. As the substitution amount (x) increased, we detected the phase transitions among the orthorhombic, cubic, and monoclinic phase driven by the compositional changes, as well as accompanied by an order-disorder-order transformation. A full range of solid solutions was formed between the Li₃Mg₂NbO₆ and Li₂TiO₃ endmembers, with no trace of other impurities. In the sample with the low substitution concentration (x = 0.2 mol), a coherent phase interface (CPI) between the cubic and orthorhombic lattices was formed with no obvious misfit dislocation or stacking fault, indicating the small differences in crystal configuration, chemical bonding properties, and subcell lattice parameters between the two phases. Besides, there were observed diverse reconstructed superlattices, one kind is that possessed a “transition form” of the two phases and was formed nearby the CPI, and the other kind was formed based on the cubic or orthorhombic lattices independently and was observed on a larger scale nearby the CPI. The preferential substitutions of the non-equivalent cations, which were determined by ionic radius, electronegativity, and local electroneutrality, and the interfacial strains would together act on the formation of these superlattices. The Q × f values measured in the microwave range increased considerably around the compositional range where the superlattices were formed, indicating that the effect of reconstructed superlattices on the intrinsic loss should not be overlooked. As proven by the dielectric response in the high-frequency range (0.5 − 1 THz), the x = 0.2 sample indeed showed extremely higher Q × f values than other ones, which illustrated that the sample with the reconstructed superlattices was related to a small lattice vibrational anharmonicity that is favorable for the low dielectric loss.

新类型的多组分锂的_{3+ X}镁_{2-2 X}的Nb _{1- X}的Ti _{2 X} Ø ₆（0≤  X  ≤1）固溶陶瓷是基于锂设计₂的TiO ₃ -Li ₃ NbO的₄ - MgO伪三元相图，研究用于微波介电应用。随着取代量（x）的增加，我们检测到由成分变化驱动的正交晶相，立方相和单斜晶相之间的相变，以及伴随的有序无序变换。锂离子之间形成了完整的固溶体₃ Mg ₂ NbO ₆和Li ₂ TiO ₃端基，无任何其他杂质。在低取代浓度的样品中（x 摩尔比为0.2 mol）时，在立方晶格和正交晶格之间形成了相干相界面（CPI），没有明显的失配位错或堆垛层错，表明两相之间的晶体构型，化学键合性质和子晶格晶格参数差异很小。此外，观察到了多种多样的重构超晶格，一种是具有两相的“过渡形式”并在CPI附近形成，另一种是独立地基于立方或正交晶格形成，并且在较大的位置观察到。在CPI附近缩放。由离子半径，电负性和局部电子中性决定的非等价阳离子的优先取代，以及界面应变将共同作用于这些超晶格的形成。的在微波范围内测得的Q  ×  f值在形成超晶格的组成范围附近显着增加，这表明重建超晶格对本征损耗的影响不容忽视。高频范围（0.5 − 1 THz）的介电响应证明，x  = 0.2样品确实显示出比其他样品高得多的Q  ×  f值，这说明具有重构超晶格的样品与少量样品相关。有利于低介电损耗的晶格振动非谐性。