Patent ID: 7800868

Claim:
A magnetoresistive (MR) sensor having improved sensitivity comprising: a first magnetic structure; a MgO barrier layer adjacent to the first magnetic structure; and a second magnetic structure adjacent to the MgO barrier layer on a side opposite the first magnetic structure, the second magnetic structure including a positive magnetostriction layer adjacent to the barrier layer, a negative magnetostriction layer, and a sense enhancing layer between the positive magnetostriction layer and the negative magnetostriction layer, wherein the second magnetic structure comprises one of a free layer and a reference layer, and wherein the MR sensor is characterized by an MR ratio of (a) at least about 30% with a resistance-area (RA) product of about 0.5 Ω·μm 2 , (b) at least about 50% with an RA product of about 0.8 Ω·μm 2 , (c) at least about 80% with an RA product of about 1.0 Ω·μm 2 , or (d) at least about 100% with an RA product of about 1.4 Ω·μm 2 .