In a recent paper, the observed K eff versus D variation in NPs of maghemite (γ-Fe 2O 3) was explained on the basis of the core-shell-surface layer (CSSL) model given by Eq.: K eff = K b + (6 K S/ D) + K sh, where K b, K S, and K sh are the anisotropy constants of spins in the core, surface layer, and a shell of thickness d, respectively. Therefore, it is important to know how the effective anisotropy constant K eff varies with size D of the NPs. The stability of the stored information in magnetic recording media depends on the anisotropy energy E a (= K eff V) of nanoparticles (NPs) of volume V or diameter D. 2Department of Physics and Astronomy, West Virginia University, Morgantown, WV, United States.1Department of Mechanical Engineering, University of Rochester, Rochester, NY, United States.For $$ Pa.Sobhit Singh 1* and Mohindar S. We have proposed a calculation method of the internal stresses induced during the solidification of the metal and during the cooling from the solidification temperature to room temperature due to the difference between the thermal expansion coefficients of metal and glass. This opens new technological application of microwires as temperature microsensors and temperature-driven microactuators for micro-electro-mechanical system devices.read more read lessĪbstract: During the preparation process of the glass-covered magnetic amorphous wires, axial, radial, and azimuthal internal stresses are induced, determining their magnetic properties. In this way, the new type of temperature microsensor/microactuator working on the principle of TE deformation has been developed. Moreover, the direct proportionality between TE deformation and the resulting increase of temperature was experimentally confirmed. That mechanical deformation is interpreted to be a consequence of the resulting Joule heating, and its amplitude is directly proportional to the applied dc current in the mentioned range. The application of an electrical current along the microwire in the range 20–35 mA results in the TE mechanical bending of fixed sample, which is recorded. We finally mention emerging applications of magnetic nanowires and nanotubes, along with the foreseen perspectives in the topic.read more read lessĪbstract: The aim of this paper has been the development of a new type of temperature microsensor/microactuator working on the principle of the thermo-elastic (TE) deformation of multilayer magnetic microwire consisting of a glass-coated Co76Si11B13 metallic core and an electroplated Co90Ni10 external shell. We also mention standard characterization techniques useful for these. For each aspect, both theory and experiments are surveyed. We then review their magnetic properties: global measurements, magnetization states and switching, single domain wall statics and dynamics, and spin waves. We first provide an overview of common fabrication methods yielding nanowires, nanotubes and structures engineered in geometry (change in diameter, shape) or material (segments, core–shell structures), shape or core–shell. These give access to ever more complex and thus functional structures, and also shifting the focus from material-type measurements of large assemblies, to single-object investigations. While the topic of nanowires and later nanotubes started now decades ago, it is nevertheless flourishing, thanks to the progress of synthesis, theory and characterization tools. The three-dimensional nature and the curvature of these objects contribute also to their specific properties, compared to patterns flat elements. At the same time, this makes the underlying physics easier to understand due to the limiter number of degrees of freedom involved. At this scale, comparable to micromagnetic and transport length scales, novel properties appear. By nano we consider diameters reasonably smaller than a micrometer. Abstract: We propose a review of the current knowledge about the synthesis, magnetic properties, and applications of magnetic cylindrical nanowires and nanotubes.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |