Synthesis and properties of α‐Fe₂O₃ nanorods

Abstract

We report synthesis of α-Fe 2 O 3 (hematite) nanorods by reverse micelles method using cetyltrimethyl ammonium bromide (CTAB) as surfactant and calcined at 300 °C. The calcined α-Fe 2 O 3 nanorods were characterized by X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The result showed that the α-Fe 2 O 3 nanorods were hexagonal structure. The nanorods have diameter of 30-50 nm and length of 120-150 nm. The weak ferromagnetic behavior was observed with saturation magnetization = 0.6 emu/g, coercive force = 25 Oe and remanant magnetization = 0.03 emu/g.

Effect of iron doping on the properties of nanopowders and coatings on the basis of Al2O3 produced by pulsed electron beam evaporation

“…In addition, the maximum magnetic moment was recorded in the Al 2 O 3 1.1% Fe sample with the minimum content of magnetic Fe ions, which is much less than the percolation threshold (usually several wt % of the dopant [64]). This fact confirms the opin ion widespread among researchers of magnetism [45,57,58,65,66] about the absence of the logical corre lation between the magnetic response and the concen tration of the magnetic dopant in the diluted magnetic semiconductors. We note that the saturation magneti zation in multiphase NP pure Al 2 O 3 and Al 2 O 3 Al in [16] (the content of Fe impurities in NP (ICP) did not exceed 6.07 × 10 -2 and 3.9 × 10 -2 wt %, respectively) reached (0.27-0.06)-(0.01-0.04) emu/g, respec tively.…”

“…Hematite is a typical antiferromagnet with a Neel temperature of 680°C. However, at room tem perature, the hematite particles (nanorods) behave like a weak ferromagnet with low saturation magneti zation on the order of 0.6 emu/g [57] and sometimes demonstrate high saturation magnetization (~13 emu/g) [58]. The appearance of ferromagnetic properties in hematite [58] was associated with a large number of point defects in the sample, since after annealing the sample became antiferromagnetic.…”

Controllable Synthesis of Single‐Crystalline Fe3O4 Nanorice by a One‐Pot, Surfactant‐Assisted Hydrothermal Method and Its Properties

“…Shape anisotropy can increase the coercivity, which arises from the alignment of the magnetic spins along the long axis and to reverse the direction requires more energy for long particles than for other shapes. [35] …”

STRUCTURAL AND MAGNETIC STUDIES OF ONE DIMENSIONAL HEMATITE (aFe2O3) NANORODS BY HYDROTHERMAL METHOD

“…One dimensional α-Fe2O3 nanorods have been studied for a wide range of applications because their magnetic properties are greatly dependent on nanorod size and shape [5] [6]. Nanorods are capable of exhibiting much higher coercivities than their isotropic counterparts because of the effect of shape anisotropy [7] [8]. To date, α-Fe2O3 nanostructures have been produced using a variety of techniques such as solgel technique, co-precipitation process, reverse micelle method, and hydrothermal/solvothermal treatment [9][10].…”