Iron oxide (ε-Fe2O3) is emerging as a promising electromagnetic material due to its unique magnetic and electronic properties. This review focuses on the intrinsic properties of ε-Fe2O3, particularly its high coercivity, comparable to that of rare-earth magnets, which is attributed to its significant magnetic anisotropy. These properties render it highly suitable for applications in millimeter wave absorption and high-density magnetic storage media. Furthermore, its semiconducting behavior offers potential applications in photocatalytic hydrogen production. The review also explores various synthesis methods for fabricating ε-Fe2O3 as nanoparticles or thin films, emphasizing the optimization of purity and stability. By exploring and harnessing the properties of ε-Fe2O3, this study aims to contribute to the advancement of next-generation electromagnetic materials with potential applications in 6G wireless telecommunications, spintronics, high-density data storage, and energy technologies.

1. Introduction 
2. Properties and Synthesis of ε-Fe2O3 
    2.1. Structure and Properties of ε-Fe2O3 
    2.2. Fabrication Methods for ε-Fe₂O3 
3. Applications of ε-Fe2O3 
    3.1. Millimeter-Wave Absorption Applications 
    3.2. High-Density Magnetic Recording Media Applications 
    3.3. Visible light catalytic Applications 
4. Summary 
Funding
Conflict of Interest 
Author Information and Contribution 
Acknowledgement
References

• Ji Hyeong Jeong(Nano Materials Research Division, Korea Institute of Materials Science, 797 Changwondaero, Changwon 51508, Republic of Korea)
• Hwan Hee Kim(Nano Materials Research Division, Korea Institute of Materials Science, 797 Changwondaero, Changwon 51508, Republic of Korea)
• Jung-Goo Lee(Nano Materials Research Division, Korea Institute of Materials Science, 797 Changwondaero, Changwon 51508, Republic of Korea)
• Youn-Kyoung Baek(Nano Materials Research Division, Korea Institute of Materials Science, 797 Changwondaero, Changwon 51508, Republic of Korea) Corresponding author