Enhancement of current-perpendicular-to-plane giant magnetoresistance by synthetic antiferromagnet free layers in single spin-valve films

The enhancement of current-perpendicular-to-plane (CPP) giant magnetoresistance (GMR) by synthetic antiferromagnet (SyAF) free layers in single spin-valve (SPV) films was studied. It was demonstrated that SyAFs as free layers dramatically enhance the CPP-GMR ratio from 0.83% to 3.56% at room temperature and double the resistance-area product in single SPV films. An experimental and single-domain thermal activation modeling study of magnetic switching behavior showed that the CPP-GMR SPV with SyAF structure approaches that of a single-domain magnet even with low aspect ratio of 1 as long as its size diminishes to ∼0.18 μm².