Li Zeya, Tang Ming, Huang Junwei, Qin Feng, Ao Lingyi, Shen Zhiwei, Zhang Caorong, Chen Peng, Bi Xiangyu, Qiu Caiyu, Yu Zhipeng, Zhai Kun, Ideue Toshiya, Wang Lin, Liu Zhongyuan, Tian Yongjun, Iwasa Yoshihiro, Yuan Hongtao
National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China.
School of Physics, Nanjing University, Nanjing, 210000, China.
Adv Mater. 2022 Jul;34(27):e2201209. doi: 10.1002/adma.202201209. Epub 2022 May 29.
The technological appeal of van der Waals ferromagnetic materials is the ability to control magnetism under external fields with desired thickness toward novel spintronic applications. For practically useful devices, ferromagnetism above room temperature or tunable magnetic anisotropy is highly demanded but remains challenging. To date, only a few layered materials exhibit unambiguous ferromagnetic ordering at room temperature via gating techniques or interface engineering. Here, it is demonstrated that the magnetic anisotropy control and dramatic modulation of Curie temperature (T ) up to 400 K are realized in layered Fe GeTe via the high-pressure diamond-anvil-cell technique. Magnetic phases manifesting with in-plane anisotropic, out-of-plane anisotropic and nearly isotropic magnetic states can be tuned in a controllable way, depicted by the phase diagram with a maximum T up to 360 K. Remarkably, the T can be gradually enhanced to above 400 K owing to the Fermi surface evolution during a pressure loading-deloading process. Such an observation sheds light on the understanding and control of emergent magnetic states in practical spintronic applications.
范德华铁磁材料的技术吸引力在于能够在外部磁场下通过控制所需厚度来实现对磁性的调控，以用于新型自旋电子学应用。对于实际可用的器件，室温以上的铁磁性或可调节的磁各向异性是迫切需求但仍具挑战性的。迄今为止，仅有少数层状材料通过门控技术或界面工程在室温下表现出明确的铁磁有序。在此，通过高压金刚石对顶砧技术在层状Fe GeTe中实现了磁各向异性控制以及高达400 K的居里温度（T）的显著调制。表现为面内各向异性、面外各向异性和近各向同性磁态的磁相可以以可控方式进行调节，由最高T达360 K的相图描述。值得注意的是，由于在压力加载 - 卸载过程中的费米面演化，T可以逐渐提高到400 K以上。这一观察结果为实际自旋电子学应用中新兴磁态的理解和控制提供了启示。
