Mandal Dipika, Bhandari Bishal, Mullurkara Suraj V, Ohodnicki Paul R
Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
ACS Appl Mater Interfaces. 2024 Jul 3;16(26):33846-33854. doi: 10.1021/acsami.4c06498. Epub 2024 Jun 20.
Exploring a convenient, scalable, yet effective broadband electromagnetic wave absorber (EMA) in the gigahertz (GHz) region is of high interest today to quench its expanding demand. Ni-Zn ferrite is considered as a potential EMA; however, their performance study as a scalable effective millimeter-length absorber is still limited. Herein, we investigated EM wave attenuation properties of NiZnFeO (NZF) samples substituting Mn ion in place of Fe as well as Zn within a widely used frequency range of 0.1-9 GHz. Through composition optimization, NiZnMnFeO (NZM0.1F) EMA demonstrates excellent microwave absorption performance accompanied by simultaneous maximum reflection loss (RL) of -50.2 dB and wide BW of 6.8 GHz (with RL < -10 dB, i.e., attenuation >90%) at an optimum thickness of 6 mm. Moreover, the attenuation constant significantly increases from ∼217 to 301 Np/m with Mn doping. The key contribution arises from magnetic-dielectric properties synergy along with enhanced dielectric and magnetic losses owing to cation chemistry and site occupation in spinel NZF. In addition, porosity is induced in the system by a controlled two-step heat treatment process that promotes total loss with multiple internal reflections of the EM wave. Furthermore, RL is simulated by varying incident EM wave angles for the NZM0.1F sample displaying its angle insensitivity up to 50°. Our results reveal NZM0.1F as a futuristic environment-friendly microwave absorber material that is suitable for practical high-frequency applications.
如今，探索一种方便、可扩展且有效的千兆赫兹（GHz）频段宽带电磁波吸收体（EMA）以满足其不断增长的需求备受关注。镍锌铁氧体被认为是一种潜在的EMA；然而，作为可扩展的有效毫米长度吸收体的性能研究仍然有限。在此，我们研究了在0.1 - 9 GHz的广泛使用频率范围内，用锰离子替代铁以及锌的NiZnFeO（NZF）样品的电磁波衰减特性。通过成分优化，NiZnMnFeO（NZM0.1F）EMA在6毫米的最佳厚度下表现出优异的微波吸收性能，同时最大反射损耗（RL）达到 - 50.2 dB，带宽为6.8 GHz（RL < - 10 dB，即衰减>90%）。此外，随着锰掺杂，衰减常数从约217显著增加到301 Np/m。关键贡献来自于磁电性能协同作用以及由于尖晶石NZF中的阳离子化学和位点占据导致的介电和磁损耗增强。此外，通过可控的两步热处理过程在系统中引入孔隙率，这促进了电磁波多次内部反射的总损耗。此外，对NZM0.1F样品通过改变入射电磁波角度模拟了RL，结果显示其在高达50°的角度范围内不敏感。我们的结果表明NZM0.1F是一种未来环保型微波吸收材料，适用于实际高频应用。
