Schmitt Christin, Rajan Adithya, Beneke Grischa, Kumar Aditya, Sparmann Tobias, Meer Hendrik, Bednarz Beatrice, Ramos Rafael, Niño Miguel Angel, Foerster Michael, Saitoh Eiji, Kläui Mathias
Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany.
WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Nano Lett. 2024 Feb 7;24(5):1471-1476. doi: 10.1021/acs.nanolett.3c02890. Epub 2024 Jan 12.
We study current-induced switching of the Néel vector in CoO/Pt bilayers to understand the underlying antiferromagnetic switching mechanism. Surprisingly, we find that for ultrathin CoO/Pt bilayers electrical pulses along the same path can lead to an increase or decrease of the spin Hall magnetoresistance signal, depending on the current density of the pulse. By comparing these results to XMLD-PEEM imaging of the antiferromagnetic domain structure before and after the application of current pulses, we reveal the details of the reorientation of the Néel vector in ultrathin CoO(4 nm). This allows us to understand how opposite resistance changes can result from a thermomagnetoelastic switching mechanism. Importantly, our spatially resolved imaging shows that regions where the current pulses are applied and regions further away exhibit different switched spin structures, which can be explained by a spin-orbit torque-based switching mechanism that can dominate in very thin films.
我们研究了CoO/Pt双层膜中电流诱导的奈尔矢量切换，以了解潜在的反铁磁切换机制。令人惊讶的是，我们发现对于超薄CoO/Pt双层膜，沿同一路径的电脉冲可导致自旋霍尔磁阻信号增加或减小，这取决于脉冲的电流密度。通过将这些结果与施加电流脉冲前后反铁磁畴结构的XMLD-PEEM成像进行比较，我们揭示了超薄CoO（4纳米）中奈尔矢量重新取向的细节。这使我们能够理解热磁弹性切换机制如何导致相反的电阻变化。重要的是，我们的空间分辨成像表明，施加电流脉冲的区域和更远的区域呈现出不同的切换自旋结构，这可以用基于自旋轨道转矩的切换机制来解释，该机制在非常薄的薄膜中可能占主导地位。
