Current-perpendicular-to-plane (cpp) read sensor with ferromagnetic buffer and seed layers

Abstract

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic buffer and seed layers is proposed for high-resolution magnetic recording. The ferromagnetic buffer layer is preferably formed of an amorphous Co—X (where X is Hf, Y, Zr, etc.) film. It provides the CPP read sensor with microstructural discontinuity from a ferromagnetic lower shield, thus facilitating the CPP read sensor to grow freely with preferred crystalline textures, and with ferromagnetic continuity to the ferromagnetic lower shield, thus acting as a portion of the ferromagnetic lower shield. The ferromagnetic seed layer is preferably formed of a polycrystalline Ni—X (where X is Pt, Pd, Rh, Ru, etc.) film. It exhibits a face-centered-cubic (fcc) structure and does not exchange-couple with the antiferromagnetic pinning layer. It provides the CPP read sensor with microstructural continuity, thus facilitating the CPP read sensor to grow with preferred crystalline textures and exhibiting good magnetic and TMR properties, and with ferromagnetic continuity to the ferromagnetic lower shield, thus also acting as another portion of the ferromagnetic lower shield and defining the lower bound of a read gap with its upper surface.

Dependencies are inferred from the claim text.