"Effect on microstructure, dielectric, and Ku-band electromagnetic behaviour of “Ni²⁺-substituted Cd–Al spinel ferrites"

IF 5.45 Q1 Physics and Astronomy

Nano-Structures & Nano-Objects Pub Date : 2026-05-01 Epub Date: 2026-05-22 DOI:10.1016/j.nanoso.2026.101699

Shikhil S. Wanjari , Amit V. Gongal , Deoram V. Nandanwar , K.G. Rewatkar , Madhukar G. Dhonde , Satish G. Goswami , Ganesh C. Vandile , Aditya V. Tiwari

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引用次数: 0

Abstract

Ni_xCd_1-xAl_0.1Fe_1.9O₄ (NCAF) (x = 0.0–1.0) nanoferrites were synthesized via the sol–gel auto-combustion route and annealed at 800 °C to investigate the effect of Ni²⁺ substitution on microstructural and high-frequency electromagnetic properties. SEM analysis revealed a gradual reduction in grain size from 0.907 μm to 0.417 μm, while HR-TEM confirmed nanosized (29.7 nm) particles. Magnetic susceptibility (χ′_AC) increased with Ni²⁺ content, indicating improved magnetic response. In the Ku-band (12.4–18 GHz) demonstrated that Ni²⁺ substitution results in slight but systematic variations in dielectric (ε′: 3.70–3.08) and magnetic (μ′: 1.10–1.27) parameters. The dielectric response exhibits weak frequency dependence, while ε″ remains relatively low, indicating moderate dielectric loss. The AC conductivity follows a frequency-dependent trend associated with hopping conduction, and non-Debye relaxation behaviour (10⁻¹¹ s) is observed. The loss tangent shows peaks (0.33 at 13.5 GHz), reflecting combined dielectric and magnetic loss contributions. Reflection loss (RL) values ranging from −13.97 to −30.52 dB were obtained for thicknesses between 1–8 mm, with improved attenuation observed near 13–15 GHz. These results indicate that Ni²⁺ substitution enables tuning of electromagnetic parameters and attenuation behaviour within the Ku-band.

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《Ni 2 +取代Cd-Al尖晶石铁氧体的微观结构、介电性能和ku波段电磁性能的影响》

采用溶胶-凝胶自燃烧法合成nixcd1 - xal0.1 fe1.90 o4 (NCAF) （x = 0.0-1.0）纳米铁氧体，并在800℃下进行退火，研究Ni 2 +取代对纳米铁氧体微观结构和高频电磁性能的影响。SEM分析显示晶粒尺寸从0.907 μm逐渐减小到0.417 μm，而HR-TEM则证实了纳米尺寸（29.7 nm）的颗粒。磁化率（χ’AC）随着Ni 2 +含量的增加而增加，表明磁响应得到改善。在ku波段（12.4-18 GHz）中，Ni 2 +取代导致介电参数（ε′：3.70-3.08）和磁参数（μ′：1.10-1.27）发生轻微但系统的变化。介电响应表现出较弱的频率依赖性，而ε″相对较低，表明介电损耗适中。交流电导率遵循与跳变传导相关的频率依赖趋势，并且观察到非德拜弛豫行为（10⁻¹¹s）。损耗切线在13.5 GHz处出现峰值（0.33），反映了介电损耗和磁损耗的综合贡献。在1-8 mm厚度范围内，反射损耗（RL）值为−13.97 ~−30.52 dB，在13-15 GHz附近，衰减有所改善。这些结果表明，Ni 2 +替代可以调整电磁参数和ku波段内的衰减行为。

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来源期刊

Nano-Structures & Nano-Objects Physics and Astronomy-Condensed Matter Physics

CiteScore

9.20

自引率

0.00%

发文量

审稿时长

22 days

期刊介绍： Nano-Structures & Nano-Objects is a new journal devoted to all aspects of the synthesis and the properties of this new flourishing domain. The journal is devoted to novel architectures at the nano-level with an emphasis on new synthesis and characterization methods. The journal is focused on the objects rather than on their applications. However, the research for new applications of original nano-structures & nano-objects in various fields such as nano-electronics, energy conversion, catalysis, drug delivery and nano-medicine is also welcome. The scope of Nano-Structures & Nano-Objects involves: -Metal and alloy nanoparticles with complex nanostructures such as shape control, core-shell and dumbells -Oxide nanoparticles and nanostructures, with complex oxide/metal, oxide/surface and oxide /organic interfaces -Inorganic semi-conducting nanoparticles (quantum dots) with an emphasis on new phases, structures, shapes and complexity -Nanostructures involving molecular inorganic species such as nanoparticles of coordination compounds, molecular magnets, spin transition nanoparticles etc. or organic nano-objects, in particular for molecular electronics -Nanostructured materials such as nano-MOFs and nano-zeolites -Hetero-junctions between molecules and nano-objects, between different nano-objects & nanostructures or between nano-objects & nanostructures and surfaces -Methods of characterization specific of the nano size or adapted for the nano size such as X-ray and neutron scattering, light scattering, NMR, Raman, Plasmonics, near field microscopies, various TEM and SEM techniques, magnetic studies, etc .