Large Magnetization in Self-assembled 1D Chain-like α-Fe₂O₃ Nanostructures Synthesized by a Facile Solvothermal Method

Abstract

The 1D chain-like α-Fe₂O₃ nanostructures were synthesized using a facile solvothermal method followed by subsequent annealing in air at 450 °C for two hours. We have investigated the microstructure and magnetic properties of the samples in detail. Field emission scanning electron microscopy revealed the formation of 1D chain-like morphology of α-Fe₂O₃ nanostructures. The presence of the pure hematite phase in all samples was confirmed by X-ray diffraction (XRD). Further, results obtained from Raman and FT-IR spectra are consistent with XRD outcomes. The magnetic studies (M-H curves) of samples exhibited a wide range of properties. The S₁ and SSUB5/SUB samples exhibit large coercivity (HSUBC/SUB) values of 878 Oe and 1092 Oe, respectively. Interestingly, large magnetization 15 emu/g and lowest HC (= 56 Oe) were observed for sample S₂ compared to all other samples. The unusual magnetic properties of the samples are due to morphology (shape, size, and self-assembled 1D orientation of particles), surface spin disorder, and (surface/interface) anisotropy of the nanoparticles.