Exchange-assisted nonlinear bit shift reduction at high linear densities in synthetic ferrimagnetic media

Abstract

Synthetic ferrimagnetic media comprised of two magnetic layers tend to exhibit larger nonlinear transition shift (NLTS) compared to single magnetic layer conventional media. NLTS is reduced by increasing the antiferromagnetic exchange field (Hex) and especially by employing a lower layer with high magnetization and thickness product (Mst). Due to the lower switching field of the stabilization layer, the position of the transition during writing is farther downstream than that of the upper layer. We suggest that, at high densities, the pinning of the lower layer transition below the nearest neighboring upper layer transition leads to a reduction of demagnetizing fields and therefore NLTS.