Ferromagnetism in two-dimensional Fe3GeTe2; Tunability by hydrostatic pressure
Ferromagnetism in two-dimensional Fe3GeTe2; Tunability by hydrostatic pressure
复制标题
二维 Fe3GeTe2 中的铁磁性；
DOI：
10.1103/physrevb.103.094429
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发表时间：
2021-03-19
影响因子：
3.7
通讯作者：
Yang, Jinbo
中科院分区：
文献类型：
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作者：
Ding, Shilei;Liang, Zhongyu;Yang, Jinbo
研究了沿易轴方向外加磁场对高各向异性范德华铁磁金属Fe3GeTe2(FGT)磁性能的影响。在常压下，居里温度T-c=180K时发生顺磁-铁磁转变，当压力增加到1.44 Gpa时，T-c单调下降15K，而磁化强度受到压力的抑制。用高压X射线衍射法研究发现，在静压作用下，Fe-Fe键长趋于缩短，Fe-Ge(Te)-Fe键角偏离90度，表明交换作用发生了改变。第一性原理计算进一步证实了压力效应。这些结果表明，直接交换作用、超交换作用和双交换作用之间的竞争在静压下的显著磁响应中起着至关重要的作用，即在较高的压力下，直接交换作用变得更强，从而导致反铁磁成分增加，从而降低T-c。该系统在静水压力下的高度可调磁性质为低维材料系统中的自旋操纵提供了可靠的途径。
We studied the effect of hydrostatic pressure on the magnetic properties of the highly anisotropic van der Waals ferromagnetic metal Fe3GeTe2 (FGT) with the field applied along the easy axis. The paramagnetic-to-ferromagnetic transition occurs at the Curie temperature T-c = 180K at ambient pressure, and T-c decreases monotonically by up to 15 K as the pressure increases up to 1.44 GPa, while the magnetization is suppressed by the pressure. By using high-pressure x-ray diffraction techniques, we found that the Fe-Fe bond lengths tend to decrease, and the Fe-Ge(Te)-Fe bond angles deviate away from 90 degrees under hydrostatic pressures, indicating the modification of the exchange interactions. First-principles calculations further confirm the pressure effects. These results suggest that the competition between direct-, super-, and double-exchange interactions plays a crucial role in the pronounced magnetic response under the hydrostatic pressure, i.e., the direct-exchange becomes stronger at a higher pressure and, hence, leading to increased antiferromagnetic components and thus deceased T-c. The highly tunable magnetic properties under hydrostatic pressure in this system provide robust routes for spin manipulation in low-dimensional material systems.