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 Néel 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.
Highlights
The capacity to propagate magnetic domain walls with spin-polarized currents underpins several schemes for information storage and processing using spintronic devices
It was recently proposed that Neel domain wall (DW) with fixed chirality could be stabilized by the Dzyaloshinskii–Moriya interaction (DMI)[8], an indirect exchange possibly occurring at the interface between a magnetic layer and a heavy metal substrate with large spin-orbit coupling[11]
We introduce a general method enabling a direct determination of the DW structure in ultrathin ferromagnets under ambient conditions
Summary
To convey the basic idea behind our method, we start by deriving analytical formulae of the magnetic field distribution at a distance d above a DW placed at x 1⁄4 0 in a perpendicularly magnetized film (Fig. 1a). The main contribution to the stray field, denoted by B>, is provided by the abrupt
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call