Nitrogen-Vacancy Magnetometry of Edge Magnetism in Pristine and Fe Implanted Thin WS₂ Flakes

We investigate the magnetic properties of tungsten disulfide (WS₂) multilayered flakes at room-temperature using wide-field quantum diamond microscopy [1-2]. Recent magnetic bulk measurements have indicated a weak ferromagnetic response in WS₂ [3]. Theoretical predictions suggested that the edges of such flakes exhibit magnetization when at least one edge of a flake is partially hydrogenated [4]. In this study, we examine pristine and Fe-implanted WS₂ thin flakes of 45-160 nm thickness, exfoliated from bulk WS₂ and transferred to nitrogen-vacancy (NV)-doped diamond substrates. We provide the first direct evidence of edge-localized stray magnetic fields, growing linearly with the applied magnetic field and reaching up to ~4.7 μT at higher magnetic fields [5]. Magnetic simulations using alternative magnetization models favor the presence of edge magnetization aligned along an axis slightly tilted from the normal to the flake’s plane, a departure from theoretical predictions that we attribute to the presence of the externally applied field [5]. [1] I. Fescenko, et al., Phys. Rev. Appl. 11, 034029 (2019). [2] S. Lamichhane, et al., ACS Nano 17, 8694 (2023). [3] J. Luo, et al., App. Phys. Lett. 124, 033104 (2024). [4] N. Huo, et al., Appl. Phys. Lett. 104, 202406 (2014). [5] I. Fescenko, et al., Adv. Fun. Mat. 35 (38), e71467 (2025).