Increased field sensitivity in Co/Cu multilayers with soft adjacent layers

The use of simple magnetic multilayers such as Co/Cu in high-sensitivity magnetic devices is limited by the high saturation field required to achieve the maximum GMR. Most GMR devices currently use spin-valve structures which exhibit significantly mailer GMP values but have a much lower saturation field, and hence a higher Sensitivity. We have demonstrated a GMR device based on Co/Cu with an integrated soft adjacent layer (SAL) structure to enhance the low field sensitivity to 60% mT(-1) in applied fields of appropriate orientation below 1 mT. This high sensitivity to smalt magnetic fields and their direction makes devices of this type well suited for a variety of applications.