Patent ID: 7672090

Claim:
A magnetoresistive sensor comprising: a pinned layer structure; a free layer; a non-magnetic, electrically conductive spacer layer sandwiched between the pinned layer and the free layer; and a hard magnetic pinning structure, adjacent to the pinned layer structure and in direct contact with the pinned layer structure, the hard magnetic pinning structure comprising an underlayer having a surface formed with an anisotropic roughness, and a layer of hard magnetic material formed on, and in direct contact with, the surface of the underlayer and being located between the underlayer and the pinned layer structure; wherein the sensor has a medium facing surface and the layer of hard magnetic material has a magnetic anisotropy oriented substantially perpendicular to the medium facing surface; wherein the underlayer has a crystal structure that is face centered cubic, face centered tetragonal hexagonal close packed or body centered cubic or body centered tetragonal.