Ultra-broadband microwave absorption of (MnFeZn) substituted CoY hexaferrites with a self-aligned sheet stacked, highly -axis oriented and multi-domain structure

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-12, Vol.11 (47), p.26285-263
• Main Authors: Liu, Yijian, Li, Haifeng, Yan, Xutao, Sun, Jihui, Zang, Jiabao, Luo, Xiang, Sun, Li, Zhang, Meijie
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta05473j

Single phase (Mn 0.2 Fe 0.2 Zn 1.2 ) x substituted Ba 2 Co 2 Fe 12 O 22 (Co 2 Y) hexaferrites with a self-aligned sheet stacked, highly c -axis oriented and multi-domain structure were fabricated to widen their electromagnetic wave (EMW) absorption band via a solid state reaction (SSR) method without an applied magnetic field. The microstructure and magnetic properties of the prepared Ba 2 Co 2−1.6 x (Mn 0.2 Fe 0.2 Zn 1.2 ) x Fe 12 O 22 ( x = 0.5, 1.0, 1.25) hexaferrites were hereby confirmed, and their EMW absorption performance was significantly superior to that of traditional ferrite-based absorbers. The minimum reflection loss (RL min ) of sample x = 0.5 was as strong as −48.4 dB at 7.19 GHz with a thickness of 2.5 mm, and the maximum effective absorption bandwidth (EAB max ) reached as wide as 10.24 GHz (7.76-18.0 GHz) with a thickness of only 1.86 mm. Notably, for samples x = 1.0 and x = 1.25, when the thickness was 3.0 mm and 3.2 mm, the EAB max was 3.61 (4.06-7.67 GHz) and 3.65 GHz (3.81-7.46 GHz), respectively, almost covering the C-band (4.0-8.0 GHz), indicating their excellent low-frequency EMW absorption performance. The excellent EMW absorption properties of the prepared Y-type hexaferrites were attributed to the multiple regulation of ion substitution, self-aligned sheet stacking, c -axis orientation and the multi-domain structure, which optimized their impedance matching and broadened their ferromagnetic resonance (FMR) frequency range. The EMW dissipation mechanism of the prepared Y-type hexaferrites included multiple reflections, natural resonance, exchange resonance, conductive loss, dipole polarization and interfacial polarization. The findings shed new light on the synthesis of hexaferrite-based EMW absorbers with a wider absorption bandwidth. Single phase Ba 2 Co 2−1.6 x (Mn 0.2 Fe 0.2 Zn 1.2 ) x Fe 12 O 22 hexaferrites with a self-aligned sheet stacked, highly c -axis oriented and multi-domain structure were fabricated to widen their electromagnetic wave absorption band without an applied magnetic field.