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As a unit for magnetic recording, magnetic particles must meet the following size requirements: their length should be shorter than the recording wavelength; their width should be significantly smaller than the recording depth; and as many magnetic particles as possible should be contained within a unit recording volume.

Nano Fe₂O₃ exhibits favorable magnetic properties and high hardness. Key magnetic iron oxide materials include soft magnetic iron oxide (α-Fe₂O₃) and magnetic recording iron oxide (γ-Fe₂O₃). Owing to their small size, single-domain structure, and high coercivity, magnetic nanoparticles can be used to produce magnetic recording materials with improved signal-to-noise ratios.

Currently, the magnetic ultrafine particles commonly used in videotapes are acicular (needle-like) particles of iron or iron oxide, such as γ-Fe₂O₃. That said, the future of magnetic recording materials faces growing competition from emerging technologies such as semiconductor-based materials and carbon nanotubes. While solid-state drives (SSDs) using semiconductor technology have now matured, it remains undeniable that traditional hard disk drives—which rely on ferromagnetic oxide recording materials—still offer the most cost-effective solution for data storage.