Spin Transport Modulation of 2D Fe₃O₄ Nanosheets Driven by Verwey Phase Transition

Realizing spin transport between heavy metal and two-dimensional (2D) magnetic materials at high Curie temperature (T_C) is crucial to advanced spintronic information storage technology. Here, environmentally stable 2D nonlayered Fe₃O₄ nanosheets are successfully synthesized using a reproducible process and found that they exhibit vortex magnetic domains at room temperature. A Verwey phase transition temperature (T_V) of ≈110 K is identified for ≈3 nm thick nanosheet through Raman characterization and spin Hall device measurement of the Pt/Fe₃O₄ bilayer. The anisotropic magnetoresistance ratio decreases near T_V, while both the spin Hall magnetoresistance ratio and spin mixing conductance (G_r) increase at T_V. As the temperature approaches 112 K, the anomalous Hall effect ratio tends to become zero. The maximum G_r reaches ≈5 × 10¹⁵ Ω^-1m^-2 due to the clean and flat interface between Pt and 2D nanosheet. The observed spin transport behavior in Pt/Fe₃O₄ spin Hall devices indicates that 2D Fe₃O₄ nanosheets possess potential for high-power micro spintronic storage devices applications.