Spin Hall torque magnetometry of Dzyaloshinskii domain walls

Abstract

Current-induced domain wall motion in the presence of the Dzyaloshinskii-Moriya interaction (DMI) is experimentally and theoretically investigated in heavy-metal/ferromagnet bilayers. The angular dependence of the current-induced torque and the magnetization structure of Dzyaloshinskii domain walls are described and quantified simultaneously in the presence of in-plane fields. We show that the DMI strength depends strongly on the heavy metal, varying by a factor of 20 between Ta and Pa, and that strong DMI leads to wall distortions not seen in conventional materials. These findings provide essential insights for understanding and exploiting chiral magnetism for emerging spintronics applications.

Current-driven domain wall motion along high perpendicular anisotropy multilayers: The role of the Rashba field, the spin Hall effect, and the Dzyaloshinskii-Moriya interaction

“…This study is currently being performed, and the results will be addressed elsewhere. 45 In the meanwhile, the 1DM results of Fig. 2 have to be considered as a first approach valid for the low-field range.…”

Large voltage-induced modification of spin-orbit torques in Pt/Co/GdOx

“…In heavy-metal/ferromagnet/oxide trilayers with strong spin-orbit coupling, Rashba and spin Hall effects can give rise to current-induced torques 1 on the ferromagnetic film that can efficiently drive magnetization switching [2][3][4][5][6][7] and domain-wall motion. [8][9][10][11][12] These spin-orbit torques (SOTs) [13][14][15] exhibit two symmetries: a Slonczewski-like (or damping-like) torque that counteracts damping and directly drives magnetization switching, 2,16 and a field-like torque that can lower the energy barrier for switching. 17 It is anticipated that devices based on SOTs may outperform those based on conventional spin-transfer torque.…”

Spontaneous domain nucleation under in-plane fields in ultrathin films with Dzyaloshinskii-Moriya interaction

“…These films have a strong DMI with a DMI-effective field H D $2200 Oe. 11 Thus, the ratio of the DMI-effective field to the in-plane anisotropy field in these films is 0.44, which is about 70% of the critical ratio required for spontaneous formation of chiral spin textures. Fig.…”

“…Note that these in-plane fields are lower than the anisotropy field for these films which is around 5000 Oe. 11 An M R /M S ratio of <1 in the presence of in-plane fields lower than the anisotropy field is indicative of a multi-domain state with stripe domain pattern. 10,12 This stripe domain pattern is expected whenever the demagnetization field exceeds the threshold for nucleation of reverse domains.…”