Magnetic Co-doped Fe ₃ O ₄ @FeOOH nanocomposites were prepared in one step using the hydrothermal synthesis process for catalyzing peroxymonosulfate (PMS) to degrade refractory methylene blue (MB) at a wide pH range (3.0–10.0).

Two-dimensional (2D) multiferroic materials are recognized as promising candidates for next-generation nanodevices due to their tunable magnetoelectric coupling and distinctive physical phenomena. In this study, we proposed a novel 2D multiferroic van der Waals heterostructure (vdWH) by stacking atomic layers of ferroelectric In₂Se₃ and ferromagnetic MnI₃. Using first-principles calculations, we found that the MnI₃/In₂Se₃ vdWH exhibit robust metallic conductivity across various spin and polarization states, preserving the distinctive band characteristics of isolated In₂Se₃ and MnI₃. However, the alignment of Fermi levels causes the conduction band minimum (CBM) and valence band maximum (VBM) of In₂Se₃ and MnI₃ to shift relative to their original band structures. Remarkably, the MnI₃/In₂Se₃ with the upward polarization state of In₂Se₃ exhibits an Ohmic contact. Switching the polarization direction of In₂Se₃ from upward to downward can transform the MnI₃/In₂Se₃ vdWH from an Ohmic contact to a p-type Schottky contact, while also modifying its dipole moment, magnetic strength and direction. Based on these properties of MnI₃/In₂Se₃ vdWH, we designed the field-effect transistors (FETs) with high on/off rates and nonvolatile data storage device. Furthermore, the Schottky barrier heights (SBHs), magnetic moment, and dipole moment of MnI₃/In₂Se₃ vdWH can also be effectively regulated by reducing the interlayer distance. With the continuous reduction of the interlayer distance of MnI₃/In₂Se₃ vdWH, its easy magnetization axis is expected to shift from in-plane to out-of-plane. These findings offer new insights for the design and development of the next-generation spintronic and nonvolatile memory nanodevices.