High-performance microwave absorbers based on (CoNiCuZn)1−xMnxFe2O4 spinel ferrites

In this work, high-entropy (HE) spinel ferrites of (FeCoNiCrM)xOy (M = Zn, Cu, and Mn) (named as HEO-Zn, HEO-Cu, and HEO-Mn, respectively) were synthesized by a simple solid-phase reaction. The as-prepared ferrite powders possess a uniform distribution of chemical components and homogeneous three-dimensional (3D) porous structures, which have a pore size ranging from tens to hundreds of nanometers. All three HE spinel ferrites exhibited ultrahigh structural thermostability at high temperatures even up to 800 °C. What is more, these spinel ferrites showed considerable minimum reflection loss (RLmin) and significantly enhanced effective absorption bandwidth (EAB). The RLmin and EAB values of HEO-Zn and HEO-Mn are about −27.8 dB at 15.7 GHz, 6.8 GHz, and −25.5 dB at 12.9 GHz, 6.9 GHz, with the matched thickness of 8.6 and 9.8 mm, respectively. Especially, the RLmin of HEO-Cu is −27.3 dB at 13.3 GHz with a matched thickness of 9.1 mm, and the EAB reaches about 7.5 GHz (10.5–18.0 GHz), which covers almost the whole X-band range. The superior absorbing properties are mainly attributed to the dielectric energy loss involving interface polarization and dipolar polarization, the magnetic energy loss referring to eddy current and natural resonance loss, and the specific functions of 3D porous structure, indicating a potential application prospect of the HE spinel ferrites as EM absorbing materials.

show abstract

“…Therefore, the best impedance matching and proper EM energy attenuation ability result in the excellent absorption performance of HEO-Cu [55].…”

Section: 𝜀″ = 1 + 2π𝑓 𝑟 𝜔𝜏mentioning

confidence: 99%

“…Moreover, at the range of 8-18 GHz, the 𝛼 of HEO−Cu is slightly lower than that of HEO−Zn but higher than that of HEO−Mn. Therefore, the best impedance matching and proper EM energy attenuation ability result in the excellent absorption performance of HEO−Cu [55].…”

Section: 𝜀″ = 1 + 2π𝑓 𝑟 𝜔𝜏mentioning

confidence: 99%

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction

et al. 2023

View full text Add to dashboard Cite

show abstract

“…This approach has been poorly investigated so far and, in the case of iron as a trivalent cation, to the best of our knowledge just in two similar cases [22–25] . For example, Musicó et al.…”

Section: Introductionmentioning

confidence: 99%

“…This approach has been poorly investigated so far and, in the case of iron as a trivalent cation, to the best of our knowledge just in two similar cases. [22][23][24][25] For example, Musicó et al prepared different high entropy spinels using a high temperature synthesis, which showed varying interesting magnetic properties depending on the elemental composition. [25] Hosseini Mohammadabadi et al studied among others the magnetic and structural properties of an entropic spinel with increasing Mn content and fascinating results were obtained.…”

Section: Introductionmentioning

confidence: 99%

“…[25] Hosseini Mohammadabadi et al studied among others the magnetic and structural properties of an entropic spinel with increasing Mn content and fascinating results were obtained. [24] Despite various studies, the magnetic interactions are still not fully understood due to the complexity of occupation and oxidation states of the cations. [26][27] The first impressive studies have been performed to unravel the complex spin-electronic models.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multi‐Method Characterization of the High‐Entropy Spinel Oxide Mn_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2Fe₂O₄: Entropy Evidence, Microstructure, and Magnetic Properties

et al. 2022

View full text Add to dashboard Cite

The novel spinel Cu0.2Co0.2Mn0.2Ni0.2Zn0.2Fe2O4 comprising six transition metal cations was successfully prepared by a solution‐combustion method followed by distinct thermal treatments. The entropic stabilization of this hexa‐metallic material is demonstrated using in situ high temperature powder X‐ray diffraction (PXRD) and directed removal of some of the constituting elements. Thorough evaluation of the PXRD data yields sizes of coherently scattering domains in the nanometre‐range. Transmission electron microscopy based methods support this finding and indicate a homogeneous distribution of the elements in the samples. The combination of 57Fe Mössbauer spectroscopy with X‐ray absorption near edge spectroscopy allowed determination of the cation occupancy on the tetrahedral and octahedral sites in the cubic spinel structure. Magnetic studies show long‐range magnetic exchange interactions which are of ferri‐ or ferromagnetic nature with an exceptionally high saturation magnetization in the range of 92–108 emu g−1 at low temperature, but also an anomaly in the hysteresis of a sample calcined at 500 °C.

show abstract

Advancements in Microwave Absorption Motivated by Interdisciplinary Research

Zhao,

Qing,

Kong

et al. 2023

Advanced Materials

View full text Add to dashboard Cite

Microwave absorption materials (MAMs) were originally developed for military purposes, but have since evolved into versatile materials with promising applications in modern technologies, including household use. Despite significant progress in bench‐side research over the past decade, MAMs remain limited in their scope and have yet to be widely adopted. This review explores the history of MAMs from first‐generation coatings to second‐generation functional absorbers, identifies bottlenecks hindering their maturation. It also presents potential solutions such as exploring broader spatial scales, advanced characterization, introducing liquid media, utilizing novel toolbox (machine learning), and proximity of lab to end‐user. Additionally, it meticulously presents compelling applications of MAMs in medicine, mechanics, energy, optics, and sensing, which go beyond absorption efficiency, along with their current development status and prospects. This interdisciplinary research direction differs from previous research which primarily focused on meeting traditional requirements (i. e., thin, lightweight, wide, and strong), and can be defined as the next generation of smart absorbers. Ultimately, the effective utilization of ubiquitous electromagnetic waves, aided by third‐generation MAMs, should be better aligned with future expectations.This article is protected by copyright. All rights reserved

show abstract

High-performance microwave absorbers based on (CoNiCuZn)1−xMnxFe2O4 spinel ferrites

Cited by 14 publications

References 65 publications

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction

Multi‐Method Characterization of the High‐Entropy Spinel Oxide Mn_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2Fe₂O₄: Entropy Evidence, Microstructure, and Magnetic Properties

Advancements in Microwave Absorption Motivated by Interdisciplinary Research

Contact Info

Product

Resources

About

High-performance microwave absorbers based on (CoNiCuZn)1−xMnxFe2O4 spinel ferrites

Cited by 14 publications

References 65 publications

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction

Multi‐Method Characterization of the High‐Entropy Spinel Oxide Mn0.2Co0.2Ni0.2Cu0.2Zn0.2Fe2O4: Entropy Evidence, Microstructure, and Magnetic Properties

Advancements in Microwave Absorption Motivated by Interdisciplinary Research

Contact Info

Product

Resources

About

Multi‐Method Characterization of the High‐Entropy Spinel Oxide Mn_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2Fe₂O₄: Entropy Evidence, Microstructure, and Magnetic Properties