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arXiv 2404.06010cond-mat.mtrl-sci
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磁场控制范德华反铁磁体中连续的Néel矢量旋转和Néel温度

Magnetic field control of continuous Néel vector rotation and Néel temperature in a van der Waals antiferromagnet

Zhuoliang Ni, Urban Seifert, Amanda V. Haglund, Nan Huang, David G. Mandrus, Leon Balents, Liang Wu

AI总结:

该研究对二维反铁磁体MnPSe₃的Néel矢量直接成像,揭示面内磁场可连续调控其取向,并在单层中于5 T下将Néel温度提升10%,应变还可使自旋翻转磁场改变一个数量级。

摘要:

在共线反铁磁体中,自旋倾向于朝外加磁场方向倾斜,从而降低系统能量。当磁场较小时,倾斜角可忽略不计,因此诱导的各向异性能显著低于交换能。然而,当反铁磁体的本征各向异性较小时,这种微小的各向异性可发挥重要作用。在本研究中,我们对二维易面反铁磁体MnPSe₃中的Néel矢量进行直接成像;在面内外加磁场下,其自旋倾斜可忽略不计。较小的固有面内各向异性使得从块体到单层的样品中,均可通过升高磁场实现Néel矢量的连续旋转。在单层样品中,外加磁场在5特斯拉时使Néel温度升高10%,因为本征各向异性与磁场诱导各向异性的结合,为原本无序的Néel矢量场的涨落设定了临界温标。我们的研究阐明了磁场诱导各向异性在具有面内各向异性的二维磁体中的作用。我们还证明,应变可将自旋翻转转变磁场强度调节一个数量级。

英文摘要:

In a collinear antiferromagnet, spins tend to cant towards the direction of an applied magnetic field, thereby decreasing the energy of the system. The canting angle becomes negligible when the magnetic field is small so that the induced anisotropic energy is substantially lower than the exchange energy. However, this tiny anisotropy can play a significant role when the intrinsic anisotropy of the antiferromagnet is small. In our work, we conduct direct imaging of the Néel vector in a two-dimensional easy-plane antiferromagnet, MnPSe$_3$, with negligible spin canting under an external in-plane magnetic field. The small inherent in-plane anisotropy allows for the continuous rotation of the Néel vector by ramping up the magnetic field in samples from the bulk to the monolayer. In monolayer samples, the applied magnetic field elevates the Néel temperature 10$\%$ at 5 tesla, as the combination of intrinsic and field-induced anisotropies set a critical temperature scale for fluctuations of the otherwise disordered Néel vector field. Our study illuminates the contribution of field-induced anisotropy in two dimensional magnets with in-plane anisotropy. We also demonstrate that the strain can tune the spin flop transition field strength by one order of magnitude.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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