Single Crystalline Magnetite Nanotubes

Abstract

We descried a method to synthesize single crystalline Fe3O4 nanotubes by wet-etching the MgO inner cores of MgO/Fe3O4 core-shell nanowires. Homogeneous Fe3O4 nanotubes with controllable length, diameter, and wall thickness have been obtained. Resistivity of the Fe3O4 nanotubes was estimated to be approximately 4 x 10-2 Omega cm at room temperature. Magnetoresistance of approximately 1% was observed at T = 77 K when a magnetic field of B = 0.7 T was applied. The synthetic strategy presented here may be extended to a variety of materials such as YBCO, PZT, and LCMO which should provide ideal candidates for fundamental studies of superconductivity, piezoelectricity, and ferromagnetism in nanoscale structures.

Iron and chromium doped titanium dioxide nanotubes for the degradation of environmental and industrial pollutants

“…7a and b. The individual peaks of O1s at 529.5 eV and Ti 2p at 458.2 and 463.9 eV (Liu et al, 2002;Huogen et al, 2007) can be clearly seen in the highresolution spectra (Fig. 7a and b), which mean that chemical state of the sample is Ti 4+ bonded with oxygen (Ti 4+ -O), which has been modified by iron and chromium doping.…”

“…Certain Ti-O-Ti building units in titanium dioxide are broken down via alkali hydrothermal treatment of titanium dioxide with NaOH, resulting in the formation of new co-ordination i.e.,Ti-O-Na and Ti-OH , lateron. Some of Na + ions were expected to be exchanged with H + ions during acid treatment and at this stage titanate sheets were exfoliated into layered n anosh eets which subsequently scroll and form nanotubes at high temperature and high pressure to avoid electrostatic repulsions within the charges and to minimize the steric repulsions between the sheet edges while the tubular morphology is retained (Chen et al, 2002b;Liu et al, 2002;Zhang et al, 2004). These H + ions were then exchanged with Fe 3+ /Cr 3+ while reaction of titanium dioxide nanotubes with their respective salts to obtain doped titanium dioxide nanotubes (Zhang et al, 2004).…”

Solvothermal Synthesis and Magnetic Property of Magnetic Chains Self‐assembled by Fe3O4 Microoctahedrons

“…[1][2][3][4][5][6] Various approaches have been reported for fabricating Fe 3 O 4 micro/nanocrystals with varied morphologies, for example, hollow spheres, nanorods, nanowires, nanopyramids, nanoplates, etc. [7][8][9][10][11][12][13][14][15] Although Fe 3 O 4 has been synthesized by various methods, the products were overwhelmingly dominated by particles with size of nanometer. With the development of the modern science, it is a great challenge to develop approaches to synthesize magnetic particles with suitable size, which helps to meet special need of biomedical fields.…”

Heterojunction metal-oxide-metal Au-Fe3O4-Au single nanowire device for spintronics

“…Low dimensionality and shape anisotropy have affected unique electron-transport behavior in 1D magnetic nanostructures. 12,21,22 Unsurpassed magnetoresistance studies require a novel architectural device with Fe 3 O 4 1D nanostructures where magnetic domains, nanocrystalline or single crystalline grains aligned in series. Additionally, Fe 3 O 4 is thermodynamically unstable with respect to Fe 2 O 3 in the presence of oxygen, known to suffer from surface reconstruction that hinders the path for spin-polarized current, predominantly at the electrode interface.…”