Hydrothermally Grown NiV Layered Double Hydroxides: A Ferromagnetic Insulator

Abstract

Layered double hydroxides (LDHs) have emerged as fascinating materials, useful for several applications owing to their intriguing properties and low‐cost synthesis via hydrothermal methods. Herein, the realization of a ferromagnetic‐insulating state in nickel vanadium (Ni:V) LDH with different molar ratios (Ni:V—1:1, 1.5:1, 2:1, 4:1, 6:1, and 10:1) is reported. The X‐ray diffraction data of Ni:V LDHs reveal that Ni:V (2:1) LDH exhibits highest peak intensity at 2θ ≈ 34.47o in comparison with other LDHs; therefore, this sample is studied with further characterization techniques. Nanosheets with an average thickness of ≈7 nm are preassembled into a 3D flower‐like structure as observed using field emission scanning electron microscopy. Transmission electron microscopy suggests a lattice spacing of 0.31 nm with polycrystalline nature of Ni:V(2:1) LDH. The energy‐dispersive X‐ray spectroscopy investigation suggests a uniform distribution of Ni, V, and O in Ni:V(2:1) LDH. A ferromagnetic ground state is found with saturation magnetization and Curie temperature of 176 emu g−1 and 22.56 K, respectively. Unusually, it exhibits an insulating state with a bandgap of ≈2.46 eV. These findings have the potential to transform the realm of magnetic/electrostatic memory materials by establishing a new path within the domain of LDHs.