CoxFey@C Composites with Tunable Atomic Ratios for Excellent Electromagnetic Absorption Properties

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetism

Background:

• Nano-magnetic absorbers require protective shells to prevent oxidation for practical use.
• Nonmagnetic shells typically reduce electromagnetic absorption by decreasing magnetic loss.
• Maintaining the magnetic core's absorption properties with a shell is a significant challenge.

Purpose of the Study:

• To design and synthesize novel CoxFey@C composites.
• To investigate the effect of a carbon shell on electromagnetic absorption properties.
• To address the challenge of preserving magnetic core absorption with a protective shell.

Main Methods:

• Synthesis of CoxFey@C composites via reduction of CoxFe3-xO4@phenolic resin.
• Characterization of material properties, including saturation magnetization (Ms).
• Evaluation of electromagnetic absorption performance, including reflection loss (RLmin) and effective frequency range.

Main Results:

• Successfully designed and synthesized CoxFey@C composites.
• The CoxFey core exhibited high saturation magnetization, contributing to magnetic loss.
• The carbon shell enhanced dielectric loss, leading to excellent electromagnetic absorption.
• Achieved RLmin of -23 dB with a 7 GHz effective frequency range (11-18 GHz) at 2 mm thickness.

Conclusions:

• The developed CoxFey@C composites demonstrate superior electromagnetic absorption properties.
• The carbon shell effectively protects the magnetic core while enhancing overall absorption.
• These findings highlight the potential of core-shell nano-magnetic absorbers for practical applications.