RECORDING PHYSICS OF KEEPERED INDUCTIVE MEDIA

Basic recording features of keepered media intended for inductive long itudinal recording are investigated. When compared with unkeepered med ia, the keepered media investigated here areshown to have narrower pul se width, PW50, higher signal and higher medium noise. In agreement wi th previous models, it is argued that the keeper layer acts as a secon d read gap and thus creates a flux aperture effect, which reduces the pulse width We further postulate that the edge of this aperture is an additional noise source. For the Sendust keepered media we evaluated, this additional noise compensates for the signal gain such that the me dium signal-to-noise ratio is not improved. Simple model calculations, which treat the keeper as a secondary read gap, are found to qualitat ively explain the measured results.