Elongation of skyrmions by Dzyaloshinskii-Moriya interaction in helimagnetic films

Distortion of skyrmions arouses much attention recently due to the exotic topologic al and dynamic properties.Investigating the formation mechanism and dynamical behavior of the deformed skyrmions promotes practical spintronic applications.Elongation,as a typical form of deformation,has been discovered both in experiments and in theories.However,the intrinsic mechanism is absent.Here,the coexistence of zero-field circular and elongated skyrmions in helimagnetic films is observed.The elongated skyrmions,which are determined by the intrinsic Dzyaloshinskii-Moriya interaction(DMI),carry the same topological charge as the circular ones and show the skyrmion Hall effect.Currentdriven dynamics reveal again the significant role of the intrinsic DMI playing in the skyrmion elongation.