Particle Size Controlled Magnetic Loss in Magnetite Nanoparticles in RF-Microwave Region

Abstract

Frequency dependant complex magnetic permeability is used to understand RF-microwave behaviour of magnetic nanoparticles in the frequency range 250 MHz to 3 GHz. The stable dispersions of Fe3O4 nanoparticles with mean size varying between 11 to 16 nm are prepared for this purpose. The effect of mean particle size and external static magnetic field over microwave absorption properties of magnetic fluid is studied. It is observed that frequency of ferrimagnetic resonance ( ), frequency of maximum absorption ( ), loss tangent (tan ) and reflection loss ( ) can be controlled by modifying mean particle size and strength of applied external static magnetic field. This kind of study can be useful for radiomicrowave devices like tunable attenuator, EM sheilder, and other applications like Hyperthermia.

Magnetite Nanoparticles (Fe3O4) for Radio-Frequency and Microwave Applications

“…Recently, Jadav et al in 2020 studied the effect of particle size on the microwave behavior of Fe 3 O 4 nanoparticles in RF region (250 MHz-3 GHz) [122]. It was observed that maximum loss tangent increases, and minimum reflection loss (RL) decreases with a increment of mean particle size.…”

“…For instance, the maximum magnetic loss was increased by 55.6% and minimum RL was decreased by 34.5% by increasing the mean size of Fe 3 O 4 nanoparticles from 11 nm to 16 nm. Figure 9 shows the magnetic loss tangent and return loss variation with frequency for 4 different nanoparticle sizes (MF1-10 nm to MF4-17 nm) in magnetic fluid [122]. The maximum loss tangent and minimum RL was achieved for 17 nm particle size (MF4) because of high magnetic permeability resulted from a large mean particle size.…”

“…The Fe 3 O 4 nanoparticles studied in this work were synthesized using co-precipitation method. Different pH variations were used to synthesize different size nanoparticles at constant temperature for the measurement of these microwave properties [122]. Similarly, the effect of particle concentration, external magnetic field, frequency dependence of RF and microwave properties [35,123,124], agglomeration effects on the effective electromagnetic properties of composites with magnetic Fe 3 O 4 nanoparticles [125,126] have been studied and reported in the literature.…”