Current-perpendicular-to-plane (CPP) read sensor with ferromagnetic amorphous buffer and polycrystalline seed layers

摘要

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic amorphous buffer and polycrystalline seed layers is disclosed for reducing a read gap, in order to perform magnetic recording at higher linear densities. The ferromagnetic amorphous buffer and polycrystalline seed layers couples to a ferromagnetic lower shield, thus acting as part of the ferromagnetic lower shield and defining the upper surface of the ferromagnetic polycrystalline seed layer as the lower bound of the read gap. In addition, a CPP TMR or GMR read sensor with nonmagnetic and ferromagnetic cap layers is also disclosed for reducing the read gap, in order to perform magnetic recording at even higher linear densities. The ferromagnetic cap layer couples to a ferromagnetic upper shield, thus acting as part of the ferromagnetic upper shield and defining the lower surface of the ferromagnetic cap layer as the upper bound of the read gap.