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arXiv 2105.04740cond-mat.mtrl-scicond-mat.mes-hall
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层状CrSiTe3薄片中的压力增强铁磁性

Pressure-enhanced ferromagnetism in layered CrSiTe3 flakes

Cheng Zhang, Yue Gu, Le Wang, Lianglong Huang, Ying Fu, Cai Liu, Shanmin Wang, Jia-Wei Mei, Xiaolong Zou, Jun-Feng Dai

摘要:

范德华层状铁磁体的研究促进了纳米自旋电子学及其应用的发展。然而,这些材料的低温铁磁特性极大地阻碍了它们的应用。在这里,我们报告的压力增强的铁磁行为在层状CrSiTe 3薄片揭示了高压磁圆二色性(MCD)测量。在环境压力下,CrSiTe 3在32.8 K时发生顺磁-铁磁相变,磁滞回线可忽略不计,表明具有软铁磁行为。在4.6GPa压力下,软铁磁体转变为硬铁磁体,在零磁场下表现为矩形磁滞回线。有趣的是,随着压力的进一步增加,矫顽场(H_c)从4.6GPa时的0.02T急剧增加到7.8GPa时的0.17T,居里温度(Tc ^h:磁滞回线闭合的温度)也从4.6GPa时的~36 K增加到7.8GPa时的~138 K。通过密度泛函理论计算进一步研究了压力对交换相互作用的影响,发现面内最近邻交换相互作用和磁晶各向异性随着压力的增加而同时增加,从而导致实验中H_c和T_c^h的增加.磁耦合与外压之间的有效相互作用为室温层状铁磁体的研究和压敏磁功能器件的设计提供了新的契机。

英文摘要:

The research on van der Waals (vdW) layered ferromagnets have promoted the development of nanoscale spintronics and applications. However, low-temperature ferromagnetic properties of these materials greatly hinder their applications. Here, we report pressure-enhanced ferromagnetic behaviours in layered CrSiTe3 flakes revealed by high-pressure magnetic circular dichroism (MCD) measurement. At ambient pressure, CrSiTe3 undergoes a paramagnetic-to-ferromagnetic phase transition at 32.8 K, with a negligible hysteresis loop, indicating a soft ferromagnetic behaviour. Under 4.6 GPa pressure, the soft ferromagnet changes into hard one, signalled by a rectangular hysteretic loop with remnant magnetization at zero field. Interestingly, with further increasing pressure, the coercive field (H_c) dramatically increases from 0.02 T at 4.6 GPa to 0.17 T at 7.8 GPa, and the Curie temperature (T_c^h: the temperature for closing the hysteresis loop) also increases from ~36 K at 4.6 GPa to ~138 K at 7.8 GPa. The influences of pressure on exchange interactions are further investigated by density functional theory calculations, which reveal that the in-plane nearest-neighbor exchange interaction and magneto-crystalline anisotropy increase simultaneously as pressure increases, leading to increased H_c and T_c^h in experiments. The effective interaction between magnetic couplings and external pressure offers new opportunities for both searching room-temperature layered ferromagnets and designing pressure-sensitive magnetic functional devices.

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