Multimetal‐Substituted Epsilon‐Iron Oxide ϵ‐Ga 0.31 Ti 0.05 Co 0.05 Fe 1.59 O 3 for Next‐Generation Magnetic Recording Tape in the Big‐Data Era

From the viewpoints of large capacity, long‐term guarantee, and low cost, interest in magnetic recording tapes has undergone a revival as an archive storage media for big data. Herein, we prepared a new series of metal‐substituted ϵ‐Fe 2 O 3 , ϵ‐Ga III 0.31 Ti IV 0.05 Co II 0.05 Fe III 1.59 O 3 , nanoparticles with an average size of 18 nm. Ga, Ti, and Co cations tune the magnetic properties of ϵ‐Fe 2 O 3 to the specifications demanded for a magnetic recording tape. The coercive field was tuned to 2.7 kOe by introduction of single‐ion anisotropy on Co II ( S =3/2) along the c‐axis. The saturation magnetization was increased by 44 % with Ga III ( S =0) and Ti IV ( S =0) substitution through the enhancement of positive sublattice magnetizations. The magnetic tape media was fabricated using an actual production line and showed a very sharp signal response and a remarkably high signal‐to‐noise ratio compared to the currently used magnetic tape.