Papers by Keyword: Nanoclusters

Abstract: The results of improving physical properties of different types of magnetic cores made of soft magnetic crystalline and amorphous alloys based on siliceous iron are presented. Methods and modes of controlling orientational, dimensional and dynamic parameters of magnetic domains by means of a uniaxially textured complex of thermomagnetic, locally laser, and plane deformation effects have been developed. As a result, in electrical magnetic cores made of anisotropic iron-silicon steels of 3407, 3408 grades a decrease in eddy-current magnetic losses by 25–35% and an increase in magnetic permeability by 1.5–2 times have been achieved.

Abstract: The paper studies applicability of individual particles of Ag-Cu nanoalloys as data bits in the next generation memory devices constructed on the phase change memory principle. To fulfill this task, the structure formation was simulated with the molecular dynamics method on cooling from the melt of Ag-Cu nanoparticles of the diameter of 2.0 – 8.0 nm of different chemical compositions (with copper content in the alloy from 10 to 50 percent), based on the modified tight-binding potential (TB-SMA). The authors investigated the influence of the size effects and the heat removal rate on the formation of the clusters structure. The investigation showed that different internal structures can be developed upon cooling from the liquid phase, so there were determined some criteria of their stability. Clusters with copper content of not more than 10% and diameters of more than 6.0 nm were isolated from the entire set of the considered particles.

Abstract: Computer simulation of vacancy clusters distribution by depth in molybdenum irradiated by alpha particles within Cascade probability method has been carried out. Cascade probability functions have been calculated taking into account energy losses for alpha particles in molybdenum and depending on number of interactions and depth of particles penetration. Microhardness comparison of calculations and modified experimental data show their satisfactory fit.

Abstract: Recent advances in the fundamental research on the alloy development, microstructure control, property evaluation for aluminum alloys and industrial technologies in Japan is introduced. The production status of aluminum in Japan is also introduced together with the activities in the aluminum organization and academic society. Some of the recent research topics, nanohetero structure and nanocluster controlling, are presented.

Abstract: Tuning the visible emission of Si nanomaterials by modifying their size and shape is one of the key issue in optoelectronics. The observed optical gain in Si-nanoclusters (NCs) has given further impulse to nanosilicon research. We develop a phenomenological model by combining the effects of surface passivation, exciton states and quantum confinement (QC). The size and passivation dependent band gap, oscillator strength, radiative lifetime and photoluminescence (PL) intensity for NCs with diameter ranging from 1.0 to 6.0 nm are presented. By controlling a set of fitting parameters, it is possible to tune the optical band gap, PL peak and intensity. In case of pure clusters, the band gap is found to decrease with increasing NC size. Furthermore, the band gap increases on passivating the surface of the cluster with hydrogen and oxygen respectively in which the effect of oxygen is more robust. Both QC and surface passivation in addition to exciton effects determine the optical and electronic properties of silicon NCs. Visible luminescence is due to radiative recombination of electrons and holes in the quantum-confined NCs. The role of surface states on the band gap as well as on the HOMO-LUMO states is also examined and a correlation is established. Our results are in conformity with other observations. The model can be extended to study the light emission from other nanostructures and may contribute towards the development of Si based optoelectronics.