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Seminars of the Research Lines
Materials for Information Technologies
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23 May 2012, 12:00 h. Sala de Seminarios, 182
Branched Oxide Nanostructures for Energy Storage Applications
Hong Jin FAN
Nanyang Technological University, Singapore |
| Branched nanowires (or referred as nanotrees, nanoforests) with tunable 3D morphology, homo or heterogeneous junction, and interface electronic alignment represent a unique system for applications in energy conversion and storage devices. Compared with 0D nanoparticles and 1D nanowires, 3D branched nanowires possess advantages including structural hierarchy, high surface areas and direct electron transport pathways. Therefore, branched nanowires are under the focus of recent research on energy materials.
In this talk, I will present our group’s recent work on the fabrication of heterobranched oxide nanomaterials with a core-shell or stem-branch structure, and demonstration of their application as electrode materials for electrochemical energy storage. I will explain a few examples that these core-shell hybrid nanostructures are advantageous over individual components due to a synergistic effect of both constituents. The materials we cover are transition oxides such as Co3O4, MnO2, NiO, Ni(OH)2, CoO, Fe2O3, all are electrochemical active materials. They can also be combined with graphene to further enhance the performance, owing to the high conductivity of graphene.
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16 March 2012, 12:00 h. Salón de Actos
Soft Magnetic Thin Film Applications at Radio Frequencies
Masahiro Yamaguchi
Department of Electrical and Communication Engineering, Tohoku University |
| Development of new passive component technologies will enable a “More-than-Moore” paradigm leading to innovative application-specific compact systems. Ferromagnetic thin film materials, having high permeability at (and above) radio frequencies, are candidate materials for use in inductive passive components that are available in the forms of vacuum-deposited and electro-deposited metallic alloys, chemically synthesized nano-particulate composites, and traditional oxides, among others. Using these materials, the development of CMOS integrated inductors and integrated electromagnetic noise suppressors for Long Term Evolution, or 3.9th Generation, cell phone RFIC and Point-of-Load one-chip DC-DC converters, is attracting great interest from both academic and industrial communities.
This lecture begins with a review of new soft magnetic thin film applications at radio frequencies for future system-in-package (SiP) and system-on-chip (SoC) technologies. Proposed in late 1970s, these thin film soft magnet applications have evolved from inductive read/write recording head technology to the frontiers of GHz frequency device applications. Discussions covered in this lecture include: (1) Development of international cross measurements of RF permeameters to evaluate RF permeability and related FMR profiles of magnetic films; (2) small signal high permeable low loss applications to CMOS integrated inductors; (3) small signal lossy application to CMOS integrated electromagnetic noise suppressor; (4) small to medium signal applications as new metal/ferromagnetic multi-stack “conductors” to suppress skin effect utilizing negative permeability beyond the FMR frequency [μr’< 0, μr”≈0; and, (5) large current permeable application to Point-of-Load type one-chip DC-DC converters. The lecture will conclude with an outlook that provides a perspective on the future of on-chip RF magnetics. |
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