Why is gamma-ferrite used in analog audio and video tape recording?

Gamma-ferrite ($\gamma$-Fe${}_2$O${}_3$) is utilized in analog audio and video tape recording because it consists of acicular (needlelike) particles that can be effectively magnetized by the magnetic field within the gap of a recording head.1

In this process, these particles are coated onto a plastic ribbon, allowing for the selective magnetization of specific portions of the material to preserve sounds and pictures as electrical signals. This medium is highly valued because recordings can be played back immediately, easily erased, and reused multiple times without a significant loss in quality. Furthermore, the use of ferrite materials extends to the recording heads themselves, which are often constructed from ferrite to facilitate the precise magnetic imprinting required for high-quality signal reproduction.21