Room-temperature spin-orbit torque in NiMnSb
Room-temperature spin-orbit torque in NiMnSb
复制标题
DOI：
10.1038/nphys3772
复制
发表时间：
2016-09-01
期刊：
影响因子：
19.6
通讯作者：
Jungwirth, T.
中科院分区：
文献类型：
--
作者：
Ciccarelli, C.;Anderson, L.;Jungwirth, T.
在金刚石相关晶格中结晶的材料，以Si和GaAs为主要例子，是现代电子学的基础。与此同时，它们的晶体结构和相对论自旋轨道耦合的反转不对称性导致了非平衡自旋极化现象的发现，这些现象现在被广泛地探索为在各种自旋电子结构中操纵磁矩的电手段。目前对这些相对论自旋轨道力矩的研究主要集中在磁性过渡金属多层膜上。在低温稀磁半导体（Ga，Mn）As中首次发现了自旋-轨道矩，迄今为止，它仍然是唯一一个在大块非中心对称铁磁体中显示这种现象的例子。在这里，我们提出了一个一般的框架，基于完整的晶体学点群，用于识别潜在的存在和非中心对称晶体中的自旋轨道力矩的对称性。在候选的室温铁磁体中，我们选择使用NiMnSb，它是磁性Heusler化合物大家族的成员。通过在NiMnSb单晶外延层中进行全电铁磁共振测量，我们检测到由预期对称性的有效场产生的室温自旋轨道转矩，并且其大小与我们的从头计算一致。
Materials that crystallize in diamond-related lattices, with Si and GaAs as their prime examples, are at the foundation of modern electronics. Simultaneously, inversion asymmetries in their crystal structure and relativistic spin-orbit coupling led to discoveries of non-equilibrium spin-polarization phenomena that are now extensively explored as an electrical means for manipulating magnetic moments in a variety of spintronic structures. Current research of these relativistic spin-orbit torques focuses primarily on magnetic transition-metal multilayers. The low-temperature diluted magnetic semiconductor (Ga,Mn)As, in which spin-orbit torques were initially discovered, has so far remained the only example showing the phenomenon among bulk non-centrosymmetric ferromagnets. Here we present a general framework, based on the complete set of crystallographic point groups, for identifying the potential presence and symmetry of spin-orbit torques in non-centrosymmetric crystals. Among the candidate room-temperature ferromagnets we chose to use NiMnSb, which is a member of the broad family of magnetic Heusler compounds. By performing all-electrical ferromagnetic resonance measurements in single-crystal epilayers of NiMnSb we detect room-temperature spin-orbit torques generated by effective fields of the expected symmetry and of a magnitude consistent with our ab initio calculations.