Ultra-high-density magnetic information storage technologies

Three approaches used to achieve ultra-high-density recording of 100 Gbit/in² are discussed. In order to overcome the thermal fluctuation problem of recorded patterns, a write head with Co-Ni-Fe poles has been developed. The Co-Ni-Fe pole generates the strongest write field. The head wrote well in media with a coercivity of 7 kOe, which is sufficiently large for ultra-high-density recording. A narrow gap Co-Ni-Fe head for perpendicular recording has also been developed. The experimental results on contact recording and a double-layer perpendicular medium are also discussed.