Abstract : The capacity to propagate magnetic domain walls with spin-polarized currents underpins several schemes for information storage and processing using spintronic devices. A key question involves the internal structure of the domain walls, which governs their response to certain current-driven torques such as the spin Hall effect. Here we show that magnetic microscopy based on a single nitrogen-vacancy defect in diamond can provide a direct determination of the internal wall structure in ultrathin ferromagnetic films under ambient conditions. We find pure Bloch walls in Ta/CoFeB(1 nm)/MgO, while left-handed Neel walls are observed in Pt/Co(0.6 nm)/AlOx. The latter indicates the presence of a sizable interfacial Dzyaloshinskii-Moriya interaction, which has strong bearing on the feasibility of exploiting novel chiral states such as skyrmions for information technologies.
J. P. Tetienne 1 T. Hingant 1 L. J. Martinez 1 S. Rohart 2 André Thiaville 2 L Herrera Diez 3 K. Garcia 3 J. P. Adam 3 J. V. Kim 3 J. F. Roch 1 Ioan Mihai Miron 4 Gilles Gaudin 4 Laurent Vila 4 B. Ocker 5 Dafiné Ravelosona 3 V. Jacques 1
1 LAC – Laboratoire Aimé Cotton
2 LPS – Laboratoire de Physique des Solides
3 IEF – Institut d’électronique fondamentale
4 SPINTEC – SPINtronique et TEchnologie des Composants
5 Singulus technology AG
