STT-MRAM Spin-Transfer Torque Switching

Spin-transfer torque (STT) is the mechanism that writes modern magnetoresistive memory (MRAM): instead of an external magnetic field, a spin-polarized current passing through a magnetic tunnel junction transfers angular momentum directly into the free layer's magnetization, and above a critical current density that torque overcomes damping and flips the layer's orientation. This simulator integrates the real macrospin Landau-Lifshitz-Gilbert-Slonczewski equation for a free-layer nanomagnet sitting on a fixed reference layer, rendering the magnetization vector precessing and switching in 3D above the tunnel barrier while electrons stream through the junction. Drive the write current past the critical threshold I_c = αH_k and watch the bit flip between the low-resistance parallel state and the high-resistance antiparallel state, with live tunnel-magnetoresistance readout exactly as a real STT-MRAM sense amplifier would read it.