Imaging and control of critical fluctuations in two-dimensional magnets
Imaging and control of critical fluctuations in two-dimensional magnets
复制标题
二维磁体中临界波动的成像和控制
DOI：
10.1038/s41563-020-0706-8
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发表时间：
2020-06-08
期刊：
影响因子：
41.2
通讯作者：
Shan, Jie
中科院分区：
文献类型：
--
作者：
Jin, Chenhao;Tao, Zui;Shan, Jie
磁光成像技术的发展使单层铁磁绝缘体CrBr 3中临界磁涨落的实时成像和控制成为可能。这种临界波动是高度相关的，原则上可以发生在任何时间和长度尺度（1）;它们控制临界现象，并可能驱动新的阶段（2，3）。虽然磁性材料中的临界现象已经使用中子散射进行了研究，但磁交流。磁化率和其他技术（4-6），直接实时成像的临界磁化波动仍然难以捉摸。在这里，我们开发了一种快速，灵敏的磁光成像显微镜，以实现宽场，实时监测的临界磁化波动在单层铁磁绝缘体CrBr 3。我们直接从波动相关性中跟踪临界现象，并观察到慢化动力学和增强的相关长度。通过对临界涨落的实时反馈控制，我们进一步实现了完全由静电门控的磁态切换。直接成像和控制2D磁体中临界波动的能力为探索临界现象和开发纳米级引擎和信息科学中的应用提供了令人兴奋的机会。
The development of a magneto-optical imaging technique enables the real-time imaging and control of critical magnetic fluctuations in the single-layer ferromagnetic insulator CrBr3.Strong magnetization fluctuations are expected near the thermodynamic critical point of a continuous magnetic phase transition. Such critical fluctuations are highly correlated and in principle can occur at any time and length scales(1); they govern critical phenomena and potentially can drive new phases(2,3). Although critical phenomena in magnetic materials have been studied using neutron scattering, magnetic a.c. susceptibility and other techniques(4-6), direct real-time imaging of critical magnetization fluctuations remains elusive. Here we develop a fast and sensitive magneto-optical imaging microscope to achieve wide-field, real-time monitoring of critical magnetization fluctuations in single-layer ferromagnetic insulator CrBr3. We track the critical phenomena directly from the fluctuation correlations and observe both slowing-down dynamics and enhanced correlation length. Through real-time feedback control of the critical fluctuations, we further achieve switching of magnetic states solely by electrostatic gating. The ability to directly image and control critical fluctuations in 2D magnets opens up exciting opportunities to explore critical phenomena and develop applications in nanoscale engines and information science.