Realization of zero skyrmion Hall angle by elongating skyrmions

Magnetic skyrmions are considered to be potential information carriers in racetrack memory. However, the skyrmion Hall effect limits the maximum speed of skyrmions along the current direction, which hampers their further application. Here, we investigate the fundamental properties of an elongated skyrmion induced by an anisotropic Dzyaloshinskii-Moriya interaction (DMI). Spin-orbit torque-driven dynamics of the elongated skyrmion under various conditions, including anisotropic DMI, Gilbert damping, and current, are also performed by a combination of micromagnetic simulations and solutions of the Thiele equation. It is found that elongated skyrmions can realize a zero skyrmion Hall angle, and the gradient of Gilbert damping is an effective method to significantly control the skyrmion Hall angle. It should be noted that the rotational symmetry breaking of the elongated skyrmions results in lower thermal stability than the circular skyrmions. Our results offer the possibility of zero skyrmion Hall angle motion, which may help guide the potential application of elongated skyrmions in racetrack memory.