Controlling spin current polarization through non-collinear antiferromagnetism
Controlling spin current polarization through non-collinear antiferromagnetism
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DOI：
10.1038/s41467-020-17999-4
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发表时间：
2020-09-16
影响因子：
16.6
通讯作者：
Eom, C. B.
中科院分区：
文献类型：
--
作者：
Nan, T.;Quintela, C. X.;Eom, C. B.
自旋霍尔效应导致的电荷流和自旋流之间的相互转换是自旋电子学的重要组成部分。当这些自旋电流的自旋极化与磁化共线时，可以实现能量有效和确定性的磁化切换。然而，对称性条件通常限制自旋极化正交的电荷和自旋流。只有当晶体对称性降低时，自旋极化才能偏离这种方向。在这里，我们通过使用非共线反铁磁体Mn 3GaN来控制自旋极化方向，其中三角形自旋结构在保持高晶体对称性的同时产生低磁对称性。我们表明，外延Mn 3GaN/坡莫合金异质结构可以产生非常规的自旋轨道扭矩在室温下对应的面外和Dresselhaus样的自旋极化，这是禁止在任何样品与双重旋转对称。我们的研究结果表明，自旋结构设计的基础上控制自旋轨道力矩的方法，使高效的反铁磁自旋电子学。在典型的自旋霍尔效应中，自旋电流、电荷电流和自旋极化都是相互垂直的，这是由对称性强制的特征。在这里，使用具有三角形自旋结构的反铁磁体，作者证明了没有垂直自旋排列的自旋霍尔效应。
The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced. Here, we show control of the spin polarization direction by using a non-collinear antiferromagnet Mn3GaN, in which the triangular spin structure creates a low magnetic symmetry while maintaining a high crystalline symmetry. We demonstrate that epitaxial Mn3GaN/permalloy heterostructures can generate unconventional spin-orbit torques at room temperature corresponding to out-of-plane and Dresselhaus-like spin polarizations which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spin-orbit torque, enabling high-efficient antiferromagnetic spintronics. In the typical spin-hall effect, spin-current, charge current, and spin polarisation are all mutually perpendicular, a feature enforced by symmetry. Here, using an anti-ferromagnet with a triangular spin structure, the authors demonstrate a spin-hall effect without a perpendicular spin alignment.