Effects of magnetic shield anneal processes determined by MFM and domain imaging

Summary form only given. Magnetic shields are employed in recording heads in order to isolate individual bits during the read back process. These can be made from various permeable materials, typically NiFe binary alloys. During the fabrication of spin valves these shields are subjected to an anneal at elevated temperatures perpendicular to the easy axis. This readily disrupts the anisotropy in the shield and can lead to stability issues in the final device. One method of minimising this effect is to anneal the shield at a higher temperature prior to spin valve deposition such that the anisotropy is thermally locked.