Synthesis, characterization and magnetic properties of Fe nanotubes

Abstract

Ordered Fe nanotube arrays with an average outer diameter of 50 nm were prepared in a porous anodic aluminium oxide template using an improved sol–gel reduction approach. The morphology was studied by transmission electron and field emission scanning electron microscopes. The x-ray diffraction result shows that the nanotube was a polycrystalline phase. The microcosmic magnetic properties were investigated by Mössbauer spectrum measurement. The result reveals that a component of the magnetic moment was found in the direction of the nanotube axis. Similarly, macroscopic magnetic measurement shows that Fe nanotube arrays have obvious anisotropy, and the easy axis is parallel to the nanotube axis.

Theoretical investigations of magnetic properties of ferromagnetic single-walled nanotubes

“…Our results are in agreement with experimental result in Ref. [3] where when the magnetic field was parallel to the tube axis, the area of the loops decreased with temperature rising. At Curie point T C , the magnetization becomes zero when the field is absent, so that the area of the loops vanishes.…”

“…In particular, considerable efforts have been made in the area of quasi-one-dimensional (1D) nanostructured materials, such as nanotubes, nanowires, and nanorods. More recently, ferromagnetic (FM) nanotubes have been successfully fabricated by various methods [1][2][3][4][5], and their magnetic properties have been investigated experimentally [3][4][5][6][7][8][9]. Magnetic nanotubes have been attracting much attention due to their potential applications, such as ultrahigh-density magnetic storage devices, biotechnology, nanomedicine, and nanoelectronic devices, etc.…”

“…This paper is organized as follows. In Section 2 we put down the Heisenberg exchange Hamiltonian of tubes based on the observation of experiment [3]. Then we briefly outline the formulas derived by use of the many-body Green's function method (MBGFM) of quantum statistical theory.…”

Magnetic correlations in ferromagnetic single-walled nanotubes

“…Following the discovery, different chemical compositions of the nanotubes have been successfully synthesized by various methods [2][3][4][5][6][7][8][9]. More recently, the enthusiasm of studying magnetic nanotubes (MNTs) has been rising from both experimental [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and theoretical [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] standpoints due to their promising applications, such as ultrahigh-density magnetic storage devices, biomagnetic sensors, nanomedicine, molecular devices, catalysts, and nanoelectronic devices, etc. Research on MNTs is expanding into newer and broader fields, including both physical properties and possible unique applications in various areas.…”

Quantum Monte Carlo simulation of the ferroelectric or ferrielectric nanowire with core shell morphology

“…Notice that the behavior of P t z is qualitatively in agreement with the theoretical and experimental results obtained in Refs. [41,47]. The dependence on the electric field E of the total transverse polarization P t x is shown in Figs.…”