Anisotropy barrier-induced unidirectional motion of spin wave driven skyrmion

Abstract

The propagation of spin waves and their interaction with the spin solitons like skyrmions, domain walls and vortex are one of the promising ways for designing nanoscale spintronic devices. Magnetic skyrmion, a particle-like nanoscale object has potential applications in next-generation spintronic devices. In this paper, the unidirectional motion of the skyrmion under the influence of spin wave is studied using micromagnetic simulations. Here, two different magnetic anisotropies are considered on a nanotrack that creates an energy gradient. As a result, the repulsive forces act on the skyrmion and is responsible for the motion of the skyrmion in one direction. The spin wave driving force leads the skyrmion to move in forward direction and the anisotropy gradient is responsible to prevent the skyrmion motion in reverse direction. The skyrmion moves from higher perpendicular magnetic anisotropy region to lower energy region, leading to a unidirectional transport of the skyrmion. This proposed device has less Joule heating and is more energy efficient as compared to other spin transfer torque (STT) and spin orbit torque (SOT) driven techniques. This is due to the fact that spin wave can generate a flow of magnetic momentum without generating an electron flow. This spin wave driven skyrmionics device is a promising pathway towards the development of a complete non-charge based magnetic devices.