Simulation study on the information storage mechanism of STT-MRAM

Spin transfer torque magnetic random access memory (STT-MRAM )[1-3] is a new type of memory that directly reversing the magnetic moment of nano-magnet by spin-polarized current to realize data storage. In this paper, the information storage mechanism of STT-MRAM and the precession reversal of the magnetic moment in the free layer of magnetic tunnel junction (MTJ) were studied and simulated based on the LLGS equation[4, 5]. As showed in the simulation results, the time needed to reverse the magnetic moment, the current density and the magnetic moment´s motion track are affected by the saturation magnetization, and the thickness, shape and damping of the free layer. With reasonable parameters, the writing time can be controlled in the range of 1×10^-9 to 5×10^-9 s with the programming current density at the level of 10¹⁰ A/m².