SPIN-TORQUE OSCILLATOR (STO) WITH ANTIPARALLEL-COUPLED FREE FERROMAGNETIC LAYERS AND MAGNETIC DAMPING

摘要

A spin-torque oscillator with antiferromagnetically-coupled free layers has at least one of the free layers with increased magnetic damping. The Gilbert magnetic damping parameter (α) is at least 0.05. The damped free layer may contain as a dopant one or more damping elements selected from the group consisting of Pt, Pd and the 15 lanthanide elements. The free layer damping may also be increased by a damping layer adjacent the free layer. One type of damping layer may be an antiferromagnetic material, like a Mn alloy. As a modification to the antiferromagnetic damping layer, a bilayer damping layer may be formed of the antiferromagnetic layer and a nonmagnetic metal electrically conductive separation layer between the free layer and the antiferromagnetic layer. Another type of damping layer may be one formed of one or more of the elements selected from Pt, Pd and the lanthanides.