Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures

Stefania Pizzini (1) , Jan Vogel (1) , Stanislas Rohart (2) , Liliana-Daniela Buda (3) , E. Jué (3) , Olivier Boulle (3) , Ioan Mihai Miron (3) , C.K. Safeer (3) , Stéphane Auffret (3) , Gilles Gaudin (3) , André Thiaville (2)

1 NEEL - MNM - Micro et NanoMagnétisme
2 LPS - Laboratoire de Physique des Solides
3 SPINTEC - SPINtronique et TEchnologie des Composants

The nucleation of reversed magnetic domains in Pt/Co/AlO$_{x}$ microstructures with perpendicular anisotropy was studied experimentally in the presence of an in-plane magnetic field. For large enough in-plane field, nucleation was observed preferentially at an edge of the sample normal to this field. The position at which nucleation takes place was observed to depend in a chiral way on the initial magnetization and applied field directions. An explanation of these results is proposed, based on the existence of a sizable Dzyaloshinskii-Moriya interaction in this sample. Another consequence of this interaction is that the energy of domain walls can become negative for in-plane fields smaller than the effective anisotropy field.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Stefania Pizzini, Jan Vogel, Stanislas Rohart, Liliana-Daniela Buda, E. Jué, et al.. Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures. Physical Review Letters, 2014, 113 (4), pp.047203. ⟨10.1103/PhysRevLett.113.047203⟩. ⟨hal-00960872v3⟩