Operation of Magnetic Vortex Transistor by Spin-Polarized Current: A Micromagnetic Approach

To avoid electron leakage and energy consumption as in present-day bipolar junction transistor, the magnetic analog of the bipolar junction transistor using magnetic vortices proves to be an excellent alternative. This alternative exploration is implemented using micromagnetic simulations, which use spin-polarized current to study the dynamics of magnetic vortices in physically separated but magnetostatically coupled nanodisks. Here, a magnetic vortex transistor (MVT), when the nanodisks are arranged in a triangular layout, is designed. Significant gain is observed for the scalene triangle configuration for a three-vortex system when the polarities of the vortices are +1, -1, +1 and for the equilateral triangular configuration when the polarities are -1, +1, +1, respectively. The mechanism of energy transfer in such magnetostatically coupled vortices has been explained in terms of the dynamics of antivortex solitons' movement through the stray field. The variation of damping parameters has no significant effect on signal transfer and amplification. Through this extensive micromagnetic calculation, the possibility of tuning the MVT by varying the configuration, polarity combination, and changing the position of the input signal is demonstrated. This study offers a prospect for nonvolatile, all magnetic information-carrying nanoscale devices and magnetic logic gates and switches.