Two-Dimensional Room-Temperature Magnetic Nonstoichiometric Fe7Se8 Nanocrystals: Controllable Synthesis and Magnetic Behavior

Zijing Zhao; Jian Zhou; Luhao Liu; Nanshu Liu; Jianqi Huang; Biao Zhang; Wei Li; Yi Zeng; Teng Zhang; Wei Ji; Teng Yang; Zhidong Zhang; Songlin Li; Yanglong Hou

doi:10.1021/acs.nanolett.1c04403

Two-Dimensional Room-Temperature Magnetic Nonstoichiometric Fe₇Se₈ Nanocrystals: Controllable Synthesis and Magnetic Behavior

Nano Lett. 2022 Feb 9;22(3):1242-1250. doi: 10.1021/acs.nanolett.1c04403. Epub 2022 Jan 21.

Authors

Zijing Zhao^{1

2}, Jian Zhou³, Luhao Liu³, Nanshu Liu⁴, Jianqi Huang⁵, Biao Zhang¹, Wei Li¹, Yi Zeng¹, Teng Zhang¹, Wei Ji⁴, Teng Yang⁵, Zhidong Zhang⁵, Songlin Li³, Yanglong Hou^{1

2}

Affiliations

¹ School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China.
² Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
³ National Laboratory of Solid-State Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
⁴ Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
⁵ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.

PMID: 35061398
DOI: 10.1021/acs.nanolett.1c04403

Abstract

Two-dimensional (2D) magnetic materials have attracted significant attention for promising applications in energy-saving logic and robust memory devices. However, most 2D magnets discovered so far typically feature drawbacks for practical applications due to low critical temperatures. Herein, we synthesize ultrathin room-temperature (RT) magnetic Fe₇Se₈ nanoflakes via the space-confined chemical vapor deposition method. It is found that the appropriate supply and control of Se concentration in the reaction chamber is crucial for synthesizing high-quality nonstoichiometric Fe₇Se₈ nanoflakes. Cryogenic electrical and magnetic characterizations reveal the emergence of spin reorientation at ∼130 K and the survival of long-range magnetic ordering up to room temperature. The RT magnetic domain structures with different thicknesses are also uncovered by magnetic force microscopy. Moreover, theoretical calculations confirm the spin configuration and metallic band structure. The outstanding characteristics exhibited by Fe₇Se₈ nanoflakes, including RT magnetism, spin reorientation property, and good electrical conductivity, make them a potential candidate for RT spintronics.

Keywords: Fe7Se8; Two-dimensional magnetic materials; nonstoichiometric compounds; room-temperature magnetic; space-confined chemical vapor deposition.