A Ferromagnetic Resonance Study of MgFe ₂ O ₄ Nanoparticles as Efficient Microwave Absorber for Different Frequency Bands

Electromagnetic (EM) wave absorption, specifically at the GHz frequency, is a technologically sound avenue from basic as well as applied science perspectives. This study reports efficient EM wave absorption properties of Magnesium Ferrite spherical nanoparticles (NP) and compares the results with its Bulk counterpart within the frequency range of 1–20 GHz. DC magnetization along with ferromagnetic resonance (FMR) spectroscopy is used to delve deep into their static and dynamic magnetic properties. Optimum impedance matching, increased interfacial polarization, higher attenuation constant along with broader FMR line width, and enhanced magnetization in NP result in superior reflection loss (RL) compared to Bulk. NP exhibits maximum RL of about −70 dB at around ∼18 GHz for 20 wt% filler content and 5.08 mm absorber thickness with an effective bandwidth of ∼4.6 GHz. The Total Absorption Power around 18 GHz, defined as the cumulative absorption behavior over a certain frequency range, is 10 times higher in NP than in Bulk. Additionally, the optimum thickness for the most efficient absorption in distinct frequency bands is also estimated for NP. These findings underline the fact that selecting the desired material in a unique morphology can dramatically enhance the EM wave absorption.