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  • 1
    Publication Date: 2015-08-06
    Description: Ferromagnetic antidot lattices are important systems for magnetic data storage and magnonic devices, and understanding their magnetization dynamics by varying their structural parameters is an important problems in magnetism. Here, we investigate the variation in spin wave spectrum in two-dimensional nanoscale Ni 80 Fe 20 antidot lattices with lattice symmetry. By varying the bias magnetic field values in a broadband ferromagnetic resonance spectrometer, we observed a stark variation in the spin wave spectrum with the variation of lattice symmetry. The simulated mode profiles showed further difference in the spatial nature of the modes between different lattices. While for square and rectangular lattices extended modes are observed in addition to standing spin wave modes, all modes in the hexagonal, honeycomb, and octagonal lattices are either localized or standing waves. In addition, the honeycomb and octagonal lattices showed two different types of modes confined within the honeycomb (octagonal) units and between two such consecutive units. Simulated internal magnetic fields confirm the origin of such a wide variation in the frequency and spatial nature of the spin wave modes. The tunability of spin waves with the variation of lattice symmetry is important for the design of future magnetic data storage and magnonic devices.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
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  • 2
    Publication Date: 2016-06-14
    Description: We have experimentally investigated the energy transfer and storage in the magnetostatically coupled vortices in a pair of disks. By measuring the frequency dependence of the rectified dc voltage, we observed a specific gyrating motion due to anomalous energy storage at the off-resonant frequency for anti-parallel polarities. Micromagnetic simulations based on the Landau-Lifshitz-Gilbert equation qualitatively reproduce the experimental results and reveal that the behavior arises from the anisotropic energy transfer, i.e., the modulation of effective damping constant of the pair disks, originating from the phase difference between coupled vortex cores. These findings can be of use in magnetic vortex based logic operations.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
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  • 3
    Publication Date: 2015-06-03
    Description: We present broadband ferromagnetic resonance measurements of tunable spin wave anisotropy in arrays of nanodots with different dot shapes. Magnetization dynamics of the circular dot array shows two modes, while square, diamond, and triangular dot arrays show three, three, and four modes, respectively. Various distinct rotational symmetries in the configurational anisotropy of the nanodot arrays are observed with the variation of dot shape. The observed spin wave modes are reproduced by micromagnetic simulations and the calculated mode profiles show different collective modes determined by internal and stray magnetic fields. Effects of dot shapes are observed in combination with the effects of lattice symmetry and the shape of the boundary of the array. The collective behaviour is observed to be weakest in the diamond shaped dots and strongest in circular shaped dots. This is further confirmed by the stray field calculation. The large variation of spin wave mode frequencies and their configurational anisotropies with dot shapes are important for selection of suitable basis structures for future magnonic crystals.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
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  • 4
    Publication Date: 2019
    Description: 〈p〉Generation and utilization of pure spin current have revolutionized energy-efficient spintronic devices. Spin pumping effect generates pure spin current, and for its increased efficiency, spin-mixing conductance and interfacial spin transparency are imperative. The plethora of reports available on generation of spin current with giant magnitude overlook the interfacial spin transparency. Here, we investigate spin pumping in β-Ta/CoFeB thin films by an all-optical time-resolved magneto-optical Kerr effect technique. From variation of Gilbert damping with Ta and CoFeB thicknesses, we extract the spin diffusion length of β-Ta and spin-mixing conductances. Consequently, interfacial spin transparency is derived as 0.50 ± 0.03 from the spin Hall magnetoresistance model for the β-Ta/CoFeB interface. Furthermore, invariance of Gilbert damping with Cu spacer layer thickness inserted between β-Ta and CoFeB layers confirms the absence of other interface effects including spin memory loss. This demonstrates a reliable and noninvasive way to determine interfacial spin transparency and signifies its role in generation of pure spin current by spin pumping effect.〈/p〉
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 5
    Publication Date: 2014-02-18
    Description: Transistors constitute the backbone of modern day electronics. Since their advent, researchers have been seeking ways to make smaller and more efficient transistors. Here, we demonstrate a sustained amplification of magnetic vortex core gyration in coupled two and three vortices by controlling their relative core polarities. This amplification is mediated by a cascade of antivortex solitons travelling through the dynamic stray field. We further demonstrated that the amplification can be controlled by switching the polarity of the middle vortex in a three vortex sequence and the gain can be controlled by the input signal amplitude. An attempt to show fan–out operation yielded gain for one of the symmetrically placed branches which can be reversed by switching the core polarity of all the vortices in the network. The above observations promote the magnetic vortices as suitable candidates to work as stable bipolar junction transistors (BJT). Scientific Reports 4 doi: 10.1038/srep04108
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
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  • 6
    Publication Date: 2013-03-16
    Description: Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging--spatially resolving the planet from its parent star--which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet's formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Konopacky, Quinn M -- Barman, Travis S -- Macintosh, Bruce A -- Marois, Christian -- New York, N.Y. -- Science. 2013 Mar 22;339(6126):1398-401. doi: 10.1126/science.1232003. Epub 2013 Mar 14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada. konopacky@di.utoronto.ca〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23493423" target="_blank"〉PubMed〈/a〉
    Keywords: Atmosphere ; *Carbon Monoxide ; *Evolution, Planetary ; Extraterrestrial Environment ; Gravitation ; *Planets ; Spectrum Analysis ; *Water
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2008-07-05
    Description: To find use in electronics, single-walled carbon nanotubes need to be efficiently separated by electronic type and aligned to ensure optimal and reproducible electronic properties. We report the fabrication of single-walled carbon nanotube (SWNT) network field-effect transistors, deposited from solution, possessing controllable topology and an on/off ratio as high as 900,000. The spin-assisted alignment and density of the SWNTs are tuned by different surfaces that effectively vary the degree of interaction with surface functionalities in the device channel. This leads to a self-sorted SWNT network in which nanotube chirality separation and simultaneous control of density and alignment occur in one step during device fabrication. Micro-Raman experiments corroborate device results as a function of surface chemistry, indicating enrichment of the specific SWNT electronic type absorbed onto the modified dielectric.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉LeMieux, Melburne C -- Roberts, Mark -- Barman, Soumendra -- Jin, Yong Wan -- Kim, Jong Min -- Bao, Zhenan -- New York, N.Y. -- Science. 2008 Jul 4;321(5885):101-4. doi: 10.1126/science.1156588.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18599781" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2016-03-31
    Description: Colonic epithelial cells are covered by thick inner and outer mucus layers. The inner mucus layer is free of commensal microbiota, which contributes to the maintenance of gut homeostasis. In the small intestine, molecules critical for prevention of bacterial invasion into epithelia such as Paneth-cell-derived anti-microbial peptides and regenerating islet-derived 3 (RegIII) family proteins have been identified. Although there are mucus layers providing physical barriers against the large number of microbiota present in the large intestine, the mechanisms that separate bacteria and colonic epithelia are not fully elucidated. Here we show that Ly6/PLAUR domain containing 8 (Lypd8) protein prevents flagellated microbiota invading the colonic epithelia in mice. Lypd8, selectively expressed in epithelial cells at the uppermost layer of the large intestinal gland, was secreted into the lumen and bound flagellated bacteria including Proteus mirabilis. In the absence of Lypd8, bacteria were present in the inner mucus layer and many flagellated bacteria invaded epithelia. Lypd8(-/-) mice were highly sensitive to intestinal inflammation induced by dextran sulfate sodium (DSS). Antibiotic elimination of Gram-negative flagellated bacteria restored the bacterial-free state of the inner mucus layer and ameliorated DSS-induced intestinal inflammation in Lypd8(-/-) mice. Lypd8 bound to flagella and suppressed motility of flagellated bacteria. Thus, Lypd8 mediates segregation of intestinal bacteria and epithelial cells in the colon to preserve intestinal homeostasis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Okumura, Ryu -- Kurakawa, Takashi -- Nakano, Takashi -- Kayama, Hisako -- Kinoshita, Makoto -- Motooka, Daisuke -- Gotoh, Kazuyoshi -- Kimura, Taishi -- Kamiyama, Naganori -- Kusu, Takashi -- Ueda, Yoshiyasu -- Wu, Hong -- Iijima, Hideki -- Barman, Soumik -- Osawa, Hideki -- Matsuno, Hiroshi -- Nishimura, Junichi -- Ohba, Yusuke -- Nakamura, Shota -- Iida, Tetsuya -- Yamamoto, Masahiro -- Umemoto, Eiji -- Sano, Koichi -- Takeda, Kiyoshi -- England -- Nature. 2016 Apr 7;532(7597):117-21. doi: 10.1038/nature17406. Epub 2016 Mar 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Immune Regulation, Department of Microbiology and Immunology, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan. ; Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, Tokyo 100-0004, Japan. ; Department of Microbiology and Infection Control, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan. ; Department of Infection Metagenomics, Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan. ; Department of Bacteriology, Okayama University Graduate School of Medicine, Okayama 700-8558, Japan. ; Department of Gastroenterology and Hepatology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan. ; Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan. ; Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan. ; Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan. ; Laboratory of Immunoparasitology, Research Institute for Microbial Diseases, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27027293" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacterial Adhesion ; Caco-2 Cells ; Cell Line ; Colitis/chemically induced/drug therapy/genetics ; Colon/*microbiology ; Dextran Sulfate ; Epithelium/*microbiology ; Female ; *Flagella ; GPI-Linked Proteins/deficiency/genetics/*metabolism/secretion ; Gram-Negative Bacteria/drug effects/metabolism/pathogenicity/*physiology ; Homeostasis ; Humans ; Inflammation/chemically induced/drug therapy/genetics ; Intestinal Mucosa/cytology/metabolism/*microbiology/secretion ; Male ; Mice ; Proteus mirabilis/drug effects/metabolism/pathogenicity ; Symbiosis
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 9
    Publication Date: 2013-01-09
    Description: Microcalcifications geographically target the location of abnormalities within the breast and are of critical importance in breast cancer diagnosis. However, despite stereotactic guidance, core needle biopsy fails to retrieve microcalcifications in up to 15% of patients. Here, we introduce an approach based on diffuse reflectance spectroscopy for detection of microcalcifications...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 64 (2000), S. 489-496 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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