Structure magnetic nanocomposite

Lamellar double hydroxides are part of, or are precursors of, a more general family of compounds designated as pillared layered structures (PLS). We quote some terms used to describe them (Mitchell 1990 Van Damme 1990). Pillared Layered Structures are nanocomposite materials prepared by linking molecules or colloids to a layered host. They exhibit a remarkably broad spectrum of structural, chemical, electronic, ionic, optical and magnetic properties, and provide supermesh host structures in which chemical reactions or physical processes can proceed under gas-phase conditions, but at liquid/solid state densities. They can be shaped as powders, pellets, or supported or self-standing Aims, and can be dispersed in solid or liquid matrices. 

An original method to fabricate oxide nanostructured magnetic materials has been proposed in Ref. [328]. The method is based on chemical modification of ion-substituted layered double hydroxides. These structures are nanocomposites based on ferromagnetic y-Fe203 nanoparticles and diamagnetic matrix, which are stable in air and have sufficient coercive force and saturation magnetization of y-Fe203. 

Weigel, T., Mohr, R., Lendlein, A. (2009), Investigation of parameters to achieve temperatures required to initiate the shape-memory effect of magnetic nanocomposites by inductive heating. Smart Materials and Structures, 18, 025011. 

W.R.Zhao, J.L. Gu, L.X. Zhang, H.R. Chen and J.L. Shi, Fabrication of Uniform Magnetic Nanocomposite Spheres with a Magnetic Core/Mesoporous Silica Shell Structure, / Am. Chem. Soc., 127, 8916-8917(2005). 

It is apparent from previous sections that magnetic nanocomposites may adopt a large variety of compositions and structures. It is also clear that the performance of these materials is closely related to the dimensions of the magnetic component, the organization of the components, and the organic-inorganic synergies. Therefore, synthetic methods must be versatile, and they must... 

Cobalt magnetic nanocomposites - top curve RDF computed from a spherical model with bulk cobalt hep structure (320 atoms) middle cobalt nanoparticles in polyphenyloxide (PRO), 4.2nm in diameter (from HRTEM) bottom cobalt nanoparticles in polyvinylpyrrolidone (PVP), 1.4nm in diameter for the bigger size, particles are structurally close to bulk metal whereas the very small size induces both a lower symmetry structure (polytetrahedral) and a strong increase of magnetization. ... 

Highly structured, 3-D nanoparticle-polymer nanocomposites possess unique magnetic, electronic, and optical properties that differ from individual entities, providing new systems for the creation of nanodevices and biosensors (Murray et al. 2000 Shipway et al. 2000). The choice of assembly interactions is a key issue in order to obtain complete control over the thermodynamics of the assembled system. The introduction of reversible hydrogen bonding and flexible linear polymers into the bricks and mortar concept gave rise to system formation in near-equilibrium conditions, providing well-defined stmctures. 

A major application of this scientific field is in the production of novel nanocomposite materials with unique characteristics. By changing the processing conditions and chemical composition of the film, it is possible to affect its structure and consequently, its physico-chemical properties. Therefore the key to a successful production of such important materials, specifically, nano structural films of predetermined optical, magnetic, dielectric,... 

Several studies focused recently on the preparation of FePt-based nanocomposites [101]. Rapid annealing of Fe/Pt multilayers leads to the formation of highly textured FePt/a-Fe nanocomposites with magnetization perpendicular to the film plane. Despite the short annealing time, FePt crystallizes in the Z,l0 phase structure, the resulting high anisotropy allowed a coercivity of 1.3 T to be obtained. 

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