1,859 research outputs found
Vortex-chain phases in layered superconductors
Layered superconductors in tilted magnetic field have a very rich spectrum of
vortex lattice configurations. In the presence of in-plane magnetic field, a
small c-axis field penetrates in the form of isolated vortex chains. The
structure of a single chain is mainly determined by the ratio of the London
[] and Josephson [] lengths, . At large the chain is composed of tilted
vortices [tilted chains] and at small it consists of a crossing array
of Josephson vortices and pancake stacks [crossing chains]. We studied the
chain structures at intermediate 's and found two types of behavior.
(I) In the range a c-axis field first penetrates in the
form of pancake-stack chains located on Josephson vortices. Due to attractive
coupling between deformed stacks, their density jumps from zero to a finite
value. With further increase of the c-axis field the chain structure smoothly
evolves into modulated tilted vortices and then transforms via a second-order
phase transition, into the tilted straight vortices. (II) In the range a c-axis field first penetrates in the form of kinks creating
kinked tilted vortices. With increasing the c-axis field this structure is
replaced via a first-order phase transition by the strongly deformed crossing
chain. This transition is accompanied by a large jump of pancake density.
Further evolution of the chain structure is similar to the higher anisotropy
scenario: it smoothly transforms back into the tilted straight vortices.Comment: Accepted to Phys. Rev. B, 20 pages 12 figures, animation of chain
structure is available in http://mti.msd.anl.gov/movies/Chains/Nl8al06Im.gif
(gif, 441 KB
The branching structure of diffusion-limited aggregates
I analyze the topological structures generated by diffusion-limited
aggregation (DLA), using the recently developed "branched growth model". The
computed bifurcation number B for DLA in two dimensions is B ~ 4.9, in good
agreement with the numerically obtained result of B ~ 5.2. In high dimensions,
B -> 3.12; the bifurcation ratio is thus a decreasing function of
dimensionality. This analysis also determines the scaling properties of the
ramification matrix, which describes the hierarchy of branches.Comment: 6 pages, 1 figure, Euro-LaTeX styl
Deep Near-Infrared Observations and Identifications of Chandra Sources in the Orion Molecular Cloud 2 and 3
We conducted deep NIR imaging observations of the Orion molecular cloud 2 and
3 using QUIRC on the 88-inch telescope of the University of Hawaii. Our
purposes are 1) to generate a comprehensive NIR source catalog of these star
forming clouds, and 2) to identify the NIR counterpart of the Chandra X-ray
sources that have no counterpart in the 2MASS catalog. Our J-, H-, and K-band
observations are about 2 mag deeper than those of 2MASS, and well match the
current Chandra observation. We detected 1448 NIR sources, for which we derived
the position, the J-, H-, and K-band magnitude, and the 2MASS counterpart.
Using this catalog, we identified the NIR counterpart for about 42% of the
2MASS-unIDed Chandra sources. The nature of these Chandra sources are discussed
using their NIR colors and spatial distributions, and a dozen protostar and
brown dwarf candidates are identified.Comment: 39 pages, 9 postscript figures, accepted for publication in A
Topological self-similarity on the random binary-tree model
Asymptotic analysis on some statistical properties of the random binary-tree
model is developed. We quantify a hierarchical structure of branching patterns
based on the Horton-Strahler analysis. We introduce a transformation of a
binary tree, and derive a recursive equation about branch orders. As an
application of the analysis, topological self-similarity and its generalization
is proved in an asymptotic sense. Also, some important examples are presented
Evaluation of pharmaceutical lifesaving skills training oriented pharmaceutical intervention
Coexistence of Superconductivity and Antiferromagnetism in Multilayered High- Superconductor HgBaCaCuO: A Cu-NMR Study
We report a coexistence of superconductivity and antiferromagnetism in
five-layered compound HgBaCaCuO (Hg-1245) with K,
which is composed of two types of CuO planes in a unit cell; three inner
planes (IP's) and two outer planes (OP's). The Cu-NMR study has revealed that
the optimallydoped OP undergoes a superconducting (SC) transition at
K, whereas the three underdoped IP's do an antiferromagnetic (AF) transition
below 60 K with the Cu moments of . Thus bulk
superconductivity with a high value of K and a static AF ordering at
K are realized in the alternating AF and SC layers. The AF-spin
polarization at the IP is found to induce the Cu moments of at
the SC OP, which is the AF proximity effect into the SC OP.Comment: 6 pages, 8 figure
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