Effect of damping constant on magnetic switching in spin torque driven perpendicular MRAM

In this paper, we present a spin torque included dynamic micromagnetic modeling investigation on the perpendicular magnetoresistive random access memory design. A small inject current always generates a steady magnetization precession of the composite storage layer around perpendicular axis. For a given current density, the precession frequency is lower when the Gilbert damping constant of the perpendicular layer is higher. It is found that magnetization reversal of the perpendicular storage layer occurs when the lateral precession frequency reaches the ferromagnetic resonance condition. To reach the required precession frequency, a higher current density is required for a great value of damping constant of the perpendicular layer.