@article{Zhang2025, 
author = {Xiaofeng Zhang and Qifan Li and Tao Wu and Zhong Yu and Xiaona Jiang and Chuanjian Wu and Zhongwen Lan and Ke Sun},
title = {Site-controlled multi-ion substitution enabling low-loss and high-permittivity microwave ferrites},
year = {2025},
journal = {Journal of Advanced Ceramics},
volume = {14},
number = {5},
pages = {9221076},
keywords = {garnet ferrites, ion substitution, ferromagnetic resonance (FMR) linewidth, dielectric constant, Curie temperature},
url = {https://www.sciopen.com/article/10.26599/JAC.2025.9221076},
doi = {10.26599/JAC.2025.9221076},
abstract = {Modern wireless communication and radar systems urgently require the application of low-loss and high-permittivity yttrium iron garnet (YIG) ferrite for highly efficient and integrated microwave circulators, isolators, filters, etc. However, achieving a high dielectric constant, low dielectric loss, and narrow ferromagnetic resonance (FMR) linewidth simultaneously is challenging. Here, we synthesized Bi–Ca–Zr co-substituted YIG ferrites and comprehensively investigated the effects of multi-ion substitution on the polycrystalline microstructure and microwave electromagnetic properties of the material. The introduction of Bi3+ ions at the crystallographic dodecahedral sites enhances the electronic polarization of single Fe3+ ions and the superexchange interaction between them. The substitution ofZr4+ ions for Fe3+ ions at octahedral sites suppresses the FMR linewidth broadening caused by magnetocrystalline anisotropy. Moreover, multi-ion substitution results in competition between liquid phase sintering and grain boundary pinning and influences the densification and grain growth processes, resulting in a non-uniform and dense microstructure composed of crystallites with a bimodal size distribution. This distinctive morphology further contributes to FMR linewidth reduction and permittivity increase. The optimized Bi–Ca–Zr co-substituted YIG ferrite has a narrow FMR linewidth of 33 Oe, high permittivity of 27, and high Curie temperature of 200 °C, making it a promising candidate for next-generation microwave devices.}
}