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

Realizing spin transport between heavy metal and two-dimensional (2D) magnetic materials at high Curie temperature (T) is crucial to advanced spintronic information storage technology. Here, environmentally stable 2D nonlayered FeO 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) of ≈110 K is identified for ≈3 nm thick nanosheet through Raman characterization and spin Hall device measurement of the Pt/FeO bilayer. The anisotropic magnetoresistance ratio decreases near T, while both the spin Hall magnetoresistance ratio and spin mixing conductance (G) increase at T. As the temperature approaches 112 K, the anomalous Hall effect ratio tends to become zero. The maximum G reaches ≈5 × 10 Ωm due to the clean and flat interface between Pt and 2D nanosheet. The observed spin transport behavior in Pt/FeO spin Hall devices indicates that 2D FeO nanosheets possess potential for high-power micro spintronic storage devices applications.