Your Story Recorded in a Magnet: Micromagnetic Simulations of Spin-Orbit Torque in Multi-layer Structures
Elizaveta Tremsina (University of California, Berkeley)
The main research focus of this project is to study some fundamental challenges in spintronics, where digital information is processed and stored via the magnetic dipole moment, encoding 1/0 bits as up/down spin direction. Existing (charge-based) memory and logic technology is greatly challenged by increasing performance demands, high power consumption, and growing production costs. Recent developments in spintronic devices that electrically store non-volatile information have proved them to be promising candidates for revolutionizing memory storage. Manipulating the magnetization to perform computations in spintronic circuits typically involves a strong magnetic field generated by a large current, leading to intense power dissipation via Joule heating. A switching mechanism called Spin Orbit Torque (SOT) is studied, whereby a charge current flowing through a heterostructure causes the accumulation of spins at the interface of a heavy metal and ferromagnet which in turn can induce magnetic switching .This happens as a result of quantum mechanical interactions of an electron’s spin and orbital angular momentum. SOT not only presents a physically interesting phenomenon but has promising applications for low-power non-volatile memory technology that have the potential to surpass the efficiencies of other spin current technologies. A GPU-accelerated micromagnetic model is employed, to simulate the dynamics of a spatially-dependent magnetization vector field. The Landau-Lifshitz-Gilbert equation is solved for structures displaying various internal spin interactions to study efficient switching mechanisms.