Noise characteristics in exchange-biased soft underlayers for perpendicular media

The characteristics of exchange-biased soft underlayers (SULs) were investigated using magnetic force microscopy and spin stand measurements with a single-pole (focused ion-beam trimmed gap) writer and magnetoresistive head. The SUL high-moment materials (FeCoB, FeAlN) were exchange biased by using IrMn. Spin stand data on perpendicular media (CoCrPtB) with an exchange-biased FeCoB SUL also showed a low integrated dc erase noise level, demonstrating its potential for use in double-layered perpendicular media.