[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

X-Ray Diffraction

Platinum-based nanostructured materials: synthesis, properties, and applications.

Designer platinum nanoparticles: Control of shape, composition in alloy, nanostructure and electrocatalytic property

A new simple and versatile technique for the phase transfer of nanoparticles from water to water-immiscible organic solvents is presented. The proposed method is based on using charged colloids as carriers for the transfer of nanoparticles with opposite surface charge. The method has been successfully applied for the transfer of SrFe12O19 nanoplatelets and CdTe nanoparticles.

Simple phase transfer of nanoparticles from aqueous to organic media using polymer colloids as carriers

Here we report the synthesis and investigation of iron and iron oxide nanowire arrays using mesoporous silica as a host material. In the present work a novel variant of synthesis of ordered magnetic nanowires in the mesoporous silica matrix was suggested. The method is based on the incorporation of a hydrophobic metal compound into the hydrophobic part of silica-surfactant composite. The amount of iron intercalated into the mesoporous matrix was measured by chemical analysis. In all samples it corresponds well to with the molar ratio SiO2: Fe = 9:1. To provide crystallinity of nanowires additional thermal treatment was performed. Thus prepared nanocomposites were characterized by TEM, ED, SAXS, SANS, BET and magnetic measurements. The anisotropy parameters of nanowires were determined using two non-correlated methods: temperature dependence of magnetic susceptibility and small angle polarized neutron scattering. It was found that the particle length increases with the increasing of the decomposition temperature of the metal complex. Obviously it deals with crystallization and growth of metal particles inside the pores at a constant diameter of a single particle. For iron containing sample annealed at 375 °C (form factor of nanowire is about 40), the coercive force at room temperature was found to be 145 Oe at saturation magnetization of 1.2 emu/g, which is not far from modern information storage. It was shown that particles shape and size are in good agreement with that of the pores. Particles are uniform and well ordered in the silica matrix. Thus, the suggested method leads to one-dimensional anisotropic nanostructures which could find an application as high-density data storage magnetic media.

The Use of Mesoporous Systems for Preparation of One-Dimensional Ordered Magnetic Nanowires

Graphene electrochemistry: ‘adiabaticity’ of electron transfer

One-dimensional photonic crystals (1D PhCs) obtained by aluminium anodizing under oscillating conditions are promising materials with structure-dependent optical properties. Electrolytes based on sulphuric, oxalic, and selenic acids have been utilized for the preparation of anodic aluminium oxide (AAO) 1D PhCs with sub-100-nm pore diameter. AAO films with larger pores can be obtained by anodizing in phosphorous acid at high voltages. Here, for the first time, anodizing in phosphorous acid is applied for the preparation of AAO 1D PhCs with nonbranched macropores. The sine wave profile of anodizing voltage in the 135–165 V range produces straight pores, whose diameter is above 100 nm and alternates periodically in size. The pore diameter modulation period linearly increases with the charge density by a factor of 599 ± 15 nm·cm2·C−1. The position of the photonic band gap is controlled precisely in the 0.63–1.96 µm range, and the effective refractive index of AAO 1D PhCs is 1.58 ± 0.05.

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One-Dimensional Photonic Crystals with Nonbranched Pores Prepared via Phosphorous Acid Anodizing of Aluminium

Porous anodic aluminum oxide (AAO) is a unique platform for many high-tech applications in nanotechnology, nanophotonics, and membrane science. Although scanning electron microscopy is the technique most widely used to...

Kirill S. Napolskii

Papers

Simple phase transfer of nanoparticles from aqueous to organic media using polymer colloids as carriers

The Use of Mesoporous Systems for Preparation of One-Dimensional Ordered Magnetic Nanowires

Graphene electrochemistry: ‘adiabaticity’ of electron transfer

One-Dimensional Photonic Crystals with Nonbranched Pores Prepared via Phosphorous Acid Anodizing of Aluminium

Birefringence in anodic aluminum oxide: an optical method for measuring porosity