68,682 research outputs found
Superconductivity and Phase Diagram in (LiFe)OHFeSeS
A series of (LiFe)OHFeSeS (0 x 1)
samples were successfully synthesized via hydrothermal reaction method and the
phase diagram is established. Magnetic susceptibility suggests that an
antiferromagnetism arising from (LiFe)OH layers coexists with
superconductivity, and the antiferromagnetic transition temperature nearly
remains constant for various S doping levels. In addition, the lattice
parameters of the both a and c axes decrease and the superconducting transition
temperature T is gradually suppressed with the substitution of S for Se,
and eventually superconductivity vanishes at = 0.90. The decrease of T
could be attributed to the effect of chemical pressure induced by the smaller
ionic size of S relative to that of Se, being consistent with the effect of
hydrostatic pressure on (LiFe)OHFeSe. But the detailed
investigation on the relationships between and the crystallographic
facts suggests a very different dependence of on anion height from
the Fe2 layer or -Fe2- angle from those in FeAs-based superconductors.Comment: 6 pages, 6 figure
More on general -brane solutions
Recently it was found that the complete integration of the
Einstein-dilaton-antisymmetric form equations depending on one variable and
describing static singly charged -branes leads to two and only two classes
of solutions: the standard asymptotically flat black -brane and the
asymptotically non-flat -brane approaching the linear dilaton background at
spatial infinity. Here we analyze this issue in more details and generalize the
corresponding uniqueness argument to the case of partially delocalized branes.
We also consider the special case of codimension one and find, in addition to
the standard domain wall, the black wall solution. Explicit relations between
our solutions and some recently found -brane solutions ``with extra
parameters'' are presented.Comment: 29 pages, 2 figure
- …