Nanowires In Matrix Research Articles

Anodic aluminium oxide templates for synthesis and study of thermal behaviour of metallic nanowires

Metallic nanowires are used as functional components of electronic devices in the form of arrays or are incorporated into nanocomposites or complex architectures with valuable properties. All three cases can be implemented on the basis of spatially ordered matrices of anodic aluminium oxide. However, as is known, the behaviour of particles enclosed in the pores of a matrix may differ from that of particles in a free state because of the influence of the interphase boundary ‘matrix – particle’. In this work, we investigate the role of the matrix in the study of the properties of metal nanowires in the matrix of anodic aluminium oxide. A significant part of the article is devoted to an overview of the methodological aspects of the characterization of their morphology, geometrical parameters and thermal behaviour. Using the example of the alumna matrix with artificially given geometrical parameters, it is shown that the temperature characteristics of phase transitions observed by differential scanning calorimetry strongly depend on the distribution of nanowires in the alumna matrix according to their size, which requires detailed processing of the data obtained for the correct definition of the corresponding temperatures of phase transitions. Copyright © 2015 John Wiley & Sons, Ltd.

Optimization of the magnetic properties of aligned Co nanowires/polymer composites for the fabrication of permanent magnets

We aim at combining high coercivity magnetic nanowires in a polymer matrix in a view to fabricate rare-earth free bonded magnets. In particular, our aim is to fabricate anisotropic materials by aligning the wires in the polymer matrix. We have explored the different parameters of the fabrication process in order to produce a material with the best possible magnetic properties. We show that the choice of a proper solvent allows obtaining stable nanowire suspensions. The length and the type of the polymer chains play also an important role. Smaller chains (Mw < 10,000) provide better magnetization results. The magnetic field applied during the casting of the material plays also a role and should be of the order of a fraction of a tesla. The local order of the nanowires in the matrix has been characterized by TEM and small angle X-ray scattering. The correlation between the local order of the wires and the magnetic properties is discussed. Materials with coercivity μ0Hc up to 0.70 T at room temperature have been obtained.