Cold sintering adjusts nanoparticle spacing to enhance dielectric resonance
Researchers used cold sintering to adjust the spacing of MXene and rare-earth iron oxide nanoparticles, enhancing their dielectric resonance properties.
A recent study published in Advanced Composites and Hybrid Materials explores the induction of dielectric resonance in composite materials through precise nanoparticle spacing. Researchers led by Chenghao Jin and Xiaojun Zeng, with contributions from Ruiwen Shu, employed a cold press sintering (CSP) technique to integrate rare-earth iron oxide nanoparticles onto molybdenum-based MXene substrates. This approach allows for the deliberate induction of dielectric resonance, characterized by the oscillation of local electrons between adjacent particles under an alternating electric field.
The CSP method operates at lower temperatures compared to traditional sintering, reducing oxidation of Mo-MXene nanosheets and preserving their electrical conductivity. This conductivity is crucial for electron supply to the magnetic nanoparticles. The study highlights that controlling the spacing between nanoparticles is key to inducing the desired dielectric response, which is fundamental for resonance-type absorption. Experiments and simulations conducted on Mo-MXene combined with CeFeOx, ErFeOx, and GdFeOx demonstrated distinct dielectric resonance features.
The findings suggest that the dielectric resonance-type loss in rare-earth magnetic materials can be modulated by the substrate and particle arrangement achieved through cold sintering. The composites showed strong magnetic stability across various temperatures, a critical factor for practical applications. Reflection loss values were used to quantify absorption performance, with the CeFeOx composite achieving -49.69 dB, GdFeOx at -40.13 dB, and ErFeOx at -33.18 dB.
All three rare-earth variants exhibited both resonance and strong absorption, indicating the technique's versatility across the Mo-MXene/ReFeOx family. Radar cross-section simulations further suggested potential applications in radar stealth technology. The researchers propose that this work offers a new design perspective for electromagnetic wave absorption materials, moving beyond traditional relaxation-loss modulation paradigms.
Source: MXenes