Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, 91405 Orsay, France.
Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay, France.
Nat Commun. 2015 Apr 1;6:6733. doi: 10.1038/ncomms7733.
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.
具有自旋极化电流的磁畴壁传播能力为使用自旋电子器件进行信息存储和处理的几种方案提供了支撑。一个关键问题涉及畴壁的内部结构，它决定了畴壁对某些电流驱动扭矩（如自旋霍尔效应）的响应。在这里，我们表明基于金刚石中单个氮空位缺陷的磁显微镜可以在环境条件下直接确定超薄铁磁薄膜中的内部壁结构。我们在 Ta/CoFeB（1nm）/MgO 中发现了纯 Bloch 壁，而在 Pt/Co（0.6nm）/AlOx 中观察到了左旋 Neel 壁。后者表明存在相当大的界面 Dzyaloshinskii-Moriya 相互作用，这对利用新型手性态（如 skyrmions）进行信息技术的可行性有很大影响。
