Prominent Verway Transition of Fe₃O₄ Thin Films Grown on Transferable Hexagonal Boron Nitride

The growth of functional oxide thin films on two-dimensional layered materials with van der Waals interactions can open up the possibility of broadening the device applications. In this paper, we report the growth of Fe3O4 (magnetite) thin films on chemically inert and insulating hexagonal boron nitride (hBN) flakes and the characterization of the crystallinity and Verway transition property of the Fe3O4 thin films. We discovered that the Fe3O4 thin film on hBN has grain structures with the energetically favorable [111] orientation on the (001) plane of hBN. The Fe3O4 thin films on hBN exhibit a resistance change owing to a Verway transition at 115 K, and the transition temperature was independent of the Fe3O4 film thickness from 35 to 240 nm. Moreover, we demonstrated the transferability of Fe3O4/hBN stacks onto SiO2/Si substrates using a transparent polymer and revealed that the Verway transition property is maintained in the transferred Fe3O4/hBN stack similarly to as-grown Fe3O4/hBN samples. Our results can open up a way of fabricating transferable devices using Fe3O4 thin films.