3,211 research outputs found
Localized Distributions of Quasi Two-Dimensional Electronic States near Defects Artificially Created at Graphite Surfaces in Magnetic Fields
We measured the local density of states of a quasi two-dimensional electron
system (2DES) near defects, artificially created by Ar-ion sputtering, on
surfaces of highly oriented pyrolytic graphite (HOPG) with scanning tunneling
spectroscopy (STS) in high magnetic fields. At valley energies of the Landau
level spectrum, we found two typical localized distributions of the 2DES
depending on the defects. These are new types of distributions which are not
observed in the previous STS work at the HOPG surface near a point defect [Y.
Niimi \textit{et al}., Phys. Rev. Lett. {\bf 97}, 236804 (2006).]. With
increasing energy, we observed gradual transformation from the localized
distributions to the extended ones as expected for the integer quantum Hall
state. We show that the defect potential depth is responsible for the two
localized distributions from comparison with theoretical calculations.Comment: 4 pages, 3 figure
Single grain (LRE)-Ba-Cu-O superconductors fabricated by top seeded melt growth in air
We have recently reported a practical processing method for the fabrication in air of large, single grain (LRE)-Ba-Cu-O [where LRE Nd, Sm, Eu and Gd] bulk superconductors that exhibit high Tc and high Jc. The process is based initially on the development of a new type of generic seed crystal that can promote effectively the epitaxial nucleation of any (RE)-Ba-Cu-O system and, secondly, by suppressing the formation of (LRE)/Ba solid solution in a controlled manner within large LRE-Ba-Cu-O grains processed in air. In this paper we investigate the degree of homogeneity of large grain Sm-Ba-Cu-O superconductors fabricated by this novel process. The technique offers a significant degree of freedom in terms of processing parameters and reproducibility in the growth of oriented single grains in air and yields bulk samples with significantly improved superconducting and field-trapping properties compared to those processed by conventional top seeded melt growth (TSMG)
Community Changes and Social Capital : Organizing Issues based on Previous Studies
MEXT-Supported Program for the Strategic Research Foundation at Private Universities (2014-2018)Forming a Social Well-being Research Consortium in Asi
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