Materials for Future High Performance Magnetic Recording Heads

Recording in the 1990s will be high density, high frequency, in-contact recording on high coercivity media. Today's state-of-the-art head materials, NiFe, Sendust and amorphous alloys, will be used in some applications. However, layered structured and artificial superlattices will become the key head technologies of the future. Use of advanced preparation techniques will allow “true” materials engineering and the fabrication of devices to incredibly accurate specifications.These very high density recording systems will require optimal inter-play between all the components—media, head, and head/media interface. Future media will be very smooth, high coercivity, large moment thin films. The head/media spacing will be less than 50 nm, and recording at more than 100 MHz will be required. Single-track heads will be replaced by very narrow track-width multitrack devices in high data rate recorders. Thin film heads will provide the answer to most of the problems of large recording fields and high frequency response. These changes will define new requirements for head materials, some of which cannot be met by currently used materials. Conventional ferrite heads will not be found in high performance recording systems; thin film inductive and magnetoresistive (MR) heads (Figure 1) will be widely used. Thin films, metals and alloys, both crystalline and amorphous, layered structures and artificial superlattices will be the key head technologies in the future. New material preparation technologies, MBE (molecular beam epitaxy), MOCVD (molecular chemical vapor deposition), sputtering, and ion beam deposition are becoming increasingly available and less expensive. These methods will be used to fabricate future devices to incredibly accurate specifications.