Gamma-Ray Irradiation Induced Ultrahigh Room-Temperature Ferromagnetism in MoS2 Sputtered Few-Layered Thin Films

Aswin kumar Anbalagan, Fang Chi Hu, Weng Kent Chan, Ashish Chhaganlal Gandhi, Shivam Gupta, Mayur Chaudhary, Kai Wei Chuang, Akhil K. Ramesh, Tadesse Billo, Amr Sabbah, Ching Yu Chiang, Yuan Chieh Tseng, Yu Lun Chueh, Sheng Yun Wu, Nyan Hwa Tai, Hsin Yi Tiffany Chen*, Chih Hao Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Defect engineering is of great interest to the two-dimensional (2D) materials community. If nonmagnetic transition-metal dichalcogenides can possess room-temperature ferromagnetism (RTFM) induced by defects, then they will be ideal for application as spintronic materials and also for studying the relation between electronic and magnetic properties of quantum-confined structures. Thus, in this work, we aimed to study gamma-ray irradiation effects on MoS2, which is diamagnetic in nature. We found that gamma-ray exposure up to 9 kGy on few-layered (3.5 nm) MoS2 films induces an ultrahigh saturation magnetization of around 610 emu/cm3 at RT, whereas no significant changes were observed in the structure and magnetism of bulk MoS2 (40 nm) films even after gamma-ray irradiation. The RTFM in a few-layered gamma-ray irradiated sample is most likely due to the bound magnetic polaron created by the spin interaction of Mo 4d ions with trapped electrons present at sulfur vacancies. In addition, density functional theory (DFT) calculations suggest that the defect containing one Mo and two S vacancies is the dominant defect inducing the RTFM in MoS2. These DFT results are consistent with Raman, X-ray photoelectron spectroscopy, and ESR spectroscopy results, and they confirm the breakage of Mo and S bonds and the existence of vacancies after gamma-ray irradiation. Overall, this study suggests that the occurrence of magnetism in gamma-ray irradiated MoS2 few-layered films could be attributed to the synergistic effects of magnetic moments arising from the existence of both Mo and S vacancies as well as lattice distortion of the MoS2 structure.

Original languageEnglish
Pages (from-to)6555-6564
Number of pages10
JournalACS Nano
Volume17
Issue number7
DOIs
StatePublished - 11 Apr 2023

Keywords

  • 2D materials
  • MoS
  • SQUID
  • density functional theory calculations
  • ferromagnetism
  • gamma-ray irradiation

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