Patent ID: 8133439

Claim:
A GMR sensor stripe formed as a lamination of horizontal planar layers of substantially identical horizontal shape and having a free layer bias point along a length dimension that is stable with respect to hysteresis, comprising: a pinned layer having a magnetic moment; a non-magnetic electrically conducting spacer layer formed on said pinned layer; a free layer having a magnetic moment and characterized by magnetic anisotropies along said length dimension and along a perpendicular width dimension, wherein said free layer has a magnetostriction that is adjustable by variations in dimension and composition of said free layer, wherein said free layer is formed on said spacer layer and weakly coupled magnetically to said pinned layer across said spacer layer; and a capping layer formed on said free layer; and wherein said layers have a length dimension that is greater than said width dimension, creating, thereby, a shape induced magnetic anisotropy in said length dimension of said free layer, maintaining a bias point of said free layer magnetic moment in a stable position along said length dimension while said free layer in a quiescent state not acted upon by external fields; and dielectric material contiguously surrounding said GMR sensor stripe placing said free layer under tensile or compressional stresses along said width dimension whereby a stress-induced anisotropy is produced in said width dimension as a result of adjusting said magnetostriction thereby canceling effects of said shape induced anisotropy in directions away from said length dimension and permitting sensitive response of said free layer magnetic moment when said free layer is not in a quiescent state, and wherein the magnetic moments of said pinned and free layers are aligned parallel to said length dimension with said stable bias point when said sensor is in a quiescent state yet whereby said free layer magnetic moment is responsive to external magnetic fields when said sensor is not in a quiescent state.