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8 1 I H I G H L I G H T S 2 0 2 3

PRINCIPAL PUBLICATION AND AUTHORS

High pressure-driven magnetic disorder and structural transformation in Fe3GeTe2: emergence of a magnetic, quantum critical point, N.-T. Dang (a,b), D.P. Kozlenko (c), O.N. Lis (c,d), S E. Kichanov (c), Y.V. Lukin (c), N.O. Golosova (c), B.N. Savenko (c), D.-L. Duong (e), T.-L. Phan (f), T.-A. Tran (g), M.-H. Phan (h), Adv. Sci. 10, 2206842 (2023); https:/doi.org/10.1002/advs.202206842 (a) Institute of Research and Development, Duy Tan University, Da Nang (Vietnam) (b) Faculty of Environmental and Natural Sciences, Duy Tan University, Da Nang (Vietnam) (c) Frank Laboratory of Neutron Physics, JINR, Dubna (Russia) (d) Kazan Federal University, Kazan (Russia) (e) IBS Center for Integrated Nanostructure Physics, Suwon (Korea) (f) Faculty of Engineering Physics and Nanotechnology, VNU-University of Engineering and Technology, Ha Noi (Vietnam) (g) Ho Chi Minh City University of Technology and Education, Ho Chi Minh (Vietnam) (h) Department of Physics, University of South Florida, Tampa (USA)

REFERENCES

[1] J.F. Sierra et al., Nat. Nanotechnol. 16, 856 (2021). [2] A.F. May et al., Phys. Rev. B 93 (2016). [3] S. Ding et al., Phys. Rev. B 103, 094429 (2021).

to PPM ≈ 15 GPa from the fit of the pressure dependences of the hyperfine fields (Figure 61). At P = 11 GPa and low temperatures, the additional paramagnetic (PM) doublet components appeared (Figure 60). At P = 17 GPa, the only paramagnetic doublets were observed in the SMS spectra, while sextet components corresponding to the ferromagnetically ordered state were fully suppressed. The hyperfine parameters as functions of pressure were determined.

PXRD and Raman spectroscopy measurements revealed the isostructural phase transformation at PC ~ 7 GPa, which is associated with the anomalous pressure behaviour of the structural parameters (the observed pressure- induced instability of the FM state in Fe3GeTe2 upon compression towards its full vanishing at PPM ~15 GPa).

Fig. 61: a) The pressure dependence of hyperfine magnetic fields at T = 10 K. b) The pressure dependence of TC of Fe3GeTe2.

Further, TC = 0 K corresponding to this pressure implies that Fe3GeTe2 is a promising candidate material in the search for a pressure-induced ferromagnetic quantum critical point (QCP). Further confirmation of the QCP realisation would require precise structural and magnetic measurements near TC = 0 K at high pressures and that the pressure-driven FM-PM state is of second-order type. This study highlights pressure as a driving force for magnetic quantum criticality in layered vdW magnetic systems.