Spin Glass State in Chemical Vapor-Deposited Crystalline Cr₂Se₃ Nanosheets

Two-dimensional (2D) magnets have raised enormous attention because of their stable long-range magnetic orders and anomalous magnetic physics at 2D limits. Spin glass states are normally discovered in disordered systems with spin frustration, which are rarely found in 2D crystalline materials. Here, the chemical vapor-deposited rhombohedral Cr₂Se₃ nanosheets could be grown down to a thickness of 1.9 nm, which have shown a hard magnetism of large coercivity of 1.5 kOe and exhibited thermal irreversibility. A spin glass state with a freezing temperature of 28 K can be estimated from an alternating-current magnetic susceptibility survey, in which unambiguous magnetic response evidence of a spin glass state in crystalline Cr₂Se₃ nanosheets was shown. An extracted short relaxation time of 10^–13 s and atomic magnetic frustration that were confirmed by neutron diffraction could strongly suggest the spin glass state with an atomically short-range magnetic order in the Cr₂Se₃ nanosheets.