Magnetic properties nanowires

This chapter deals with the selective preparation, TEM/EXAFS/XPS characterization and catalysis of mono- and bimetallic nanowires and nanoparticles highly ordered in silica FSM-16, organosilica HMM-1 and mesoporous silica thin films. The mechanism of nanowire formation is discussed with the specific surface-mediated reactions of metal precursors in the restraint of nanoscale void space of mesoporous silica templates. The unique catalytic performances of nanowires and particles occluded in mesoporous cavities are also reviewed in terms of their shape and size dependency in catalysis as well as their unique electronic and magnetic properties for the device application. 

In the above sections, our attention was primarily focused on the structural and optical properties of lanthanide doped in nanoparticles such as spherical QDs. Lanthanides doped in some other novel low-dimensional nanostructures including core-shell, one-dimensional (ID) nanowires and nanotubes, two-dimensional (2D) nanofilms, hollow nanospheres, 2D nanosheets and nanodisks have also attracted extensive attention. It is expected that their unique structures could result in unusual mechanical, electronic, optical and magnetic properties. So far few papers have been reported for lanthanide ions other than Eu3+ in these materials. Much attention is focused on the optical properties of Eu3+ ions in view of their very good spectroscopic properties. 

Zeng, H., Zheng, M., Skomski, R., Sellmyer, D. J., Liu, Y., Menon, L., and Bandyopadhyay, S., Magnetic properties of self-assembled Co nanowires of varying length and diameter. /. Appl. Phys. 87, 4718 (2000). 

After an introduction to methods of electronic structure calculations, we review how recent trends translate into the description of magnetic nanostructures. Among the considered structures are nanowires, small particles, surfaces and interfaces, and multilayers, and emphasis is on magnetic properties such as moment and magnetization, interatomic exchange, and anisotropy. 

Fe[010] chain), respectively. Since free-standing nanowires of elemental metals are one-dimensional objects, they exhibit magnetic properties similar to free standing clusters, i.e. its magnetic moment increases especially for the atoms at surface. The lower coordinated atoms have higher moment, while atoms inside of the nanostructure have magnetic moment close to the bulk values. 

Nickel-mesoporous silicon structures are of considerable industrial interest for various applications. Anisotropy of magnetic properties of the nickel nanowires inside porous silicon conditioned by their high aspect ratio is applicable for the magnetic store production [1], Moreover, these structures offer much promise for the rectenna (a special type of antenna that is used to directly convert microwave energy into DC electricity) fabrication. So, it is of value to study in detail the process of the nickel electrodeposition into pores of porous silicon and elaborate control methods for pore filling with metal. 

M. Pregelj, P. Umek, B. Drolc, B. Jancar, Z. Jaglicic, R. Dominko, and D. Arcon, Synthesis, structure, and magnetic properties of iron-oxide nanowires, J. Mater. Res., 21,2955-2962 (2006). 

Semiconducting one-dimensional (ID) nanolibers or nanowires are of interest for a wide variety of applications including interconnects, functional devices, and molecular sensors as well as for fundamental physics studies. Devices have been fabricated fi om semiconductor, and carbon nanotubes, and more recently from ICP nanofibers. It has been predicted that ICP nanofibers will have unique electrical, optical, and magnetic properties [134]. Several different methods for producing these ICP nanofibers have been developed with or without the aid of a template. The template-based methods involve synthesizing a tubular structure of the ICP within the pores of a support membrane, such as an alumina membrane [135] or a track-etched polycarbonate membrane [136]. However, more recent work has... 

As the dimensionality of metals is reduced from the 3-dimensional bulk system to the 1-dimensional wire, the electronic or magnetic properties are changed drastically [26], With the advancement in the experimental techniques to fabricate the metal nanowires, we anticipate the possibilities of incorporating them in futuristic electronic/optoelectronic devices such as quantum devices, magnetic storage, nanoprobes, and spintronics. 

Kahn, H.R., Retrikowski, K. Anisotropic stmctuial and magnetic properties of arrays of Fe26Ni74 nanowires electrodeposited in the pores of anodic alumina. J. Magn. Magn. Mater. 215-216, 526-528 (2000)... 

Kazadi, A., Bantu, M., Rivas, J., Zaragoza, G., Lopez-Quintela, M.A., Blanco, M.C. Influence of the synthesis parameters on the crystallization and magnetic properties of cobalt nanowires. J. Non-Cryst. Solids 287, 5-9 (2001)... 

Zhang T, Jin C, Zhang J, Lu X, Qian T, Li X. Microstructure and magnetic properties of ordered Lao.62Pbo.38Mn03 nanowire arrays. Nanotechnology 2005 16. 

Carbothermal route provides a general method for preparing crystaUine nanowires of oxides such as ZnO, Al Oj and Ga Oj, nitrides such as AIN and SijN, and carbides such as SiC [3], The set-up employed for the synthesis of oxide nanomaterials is shown in Figure 3.1. The method has enabled the synthesis of crystalhne nanowires of both silica and sihcon. In the case of GaN, it has been possible to dope it with Mn, Mg and Si to bestow useful optical and magnetic properties. Carbothermal reaction involving Ga Oj powder mixed with activated carbon or carbon nanotubes carried out at 1100 °C in flowing Ar yields nanowires, nanorods as well as novel nanostructures... 

Dolgiy AL, Redko SV, Komissarov I, Bondarenko VP, Yanushkevich KI, Prischepa SL (2013) Structural and magnetic properties of Ni nanowires grown in mesoporous silicon templates. Thin Solid Films 543 133... 

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