Qaiumzadeh Alireza, Skarsvåg Hans, Holmqvist Cecilia, Brataas Arne
Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
Phys Rev Lett. 2017 Mar 31;118(13):137201. doi: 10.1103/PhysRevLett.118.137201. Epub 2017 Mar 29.
Antiferromagnets may exhibit spin superfluidity since the dipole interaction is weak. We seek to establish that this phenomenon occurs in insulators such as NiO, which is a good spin conductor according to previous studies. We investigate nonlocal spin transport in a planar antiferromagnetic insulator with a weak uniaxial anisotropy. The anisotropy hinders spin superfluidity by creating a substantial threshold that the current must overcome. Nevertheless, we show that applying a high magnetic field removes this obstacle near the spin-flop transition of the antiferromagnet. Importantly, the spin superfluidity can then persist across many micrometers, even in dirty samples.
由于偶极相互作用较弱，反铁磁体可能会表现出自旋超流性。我们试图证实这种现象发生在诸如NiO之类的绝缘体中，根据先前的研究，NiO是一种良好的自旋导体。我们研究了具有弱单轴各向异性的平面反铁磁绝缘体中的非局域自旋输运。这种各向异性通过产生电流必须克服的相当大的阈值来阻碍自旋超流性。然而，我们表明，施加高磁场会在反铁磁体的自旋翻转转变附近消除这一障碍。重要的是，即使在脏样品中，自旋超流性随后也能在许多微米范围内持续存在。
