7,157 research outputs found
Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}
Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around
1/3 was investigated by neutron diffraction experiments. When the stripe order
is formed at high temperature, incommensurability \epsilon of the stripe order
has a tendency to show the value close to 1/3 for the samples with x at both
sides of 1/3. With decreasing temperature, however, \epsilon becomes close to
the value determined by the linear relation of \epsilon = n_h, where n_h is a
hole concentration. This variation of the \epsilon strongly affects the
character of the stripe order through the change of the carrier densities in
stripes and antiferromagnetic domains.Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev.
Development of Cu-spin correlation in Bi_1.74_Pb_0.38_Sr_1.88_Cu_1-y_Zn_y_O_6+d_ high-temperature superconductors observed by muon spin relaxation
A systematic muon-spin-relaxation study in Bi-2201 high-Tc cuprates has
revealed for the first time that the Cu-spin correlation (CSC) is developed at
low temperatures below 2 K in a wide range of hole concentration where
superconductivity appears. The CSC tends to become weak gradually with
increasing hole-concentration. Moreover, CSC has been enhanced through the 3%
substitution of Zn for Cu. These results are quite similar to those observed in
La-214 high-Tc cuprates. Accordingly, it has been suggested that the intimate
relation between the so-called spin-charge stripe correlations and
superconductivity is a universal feature in hole-doped high-Tc cuprates.
Furthermore, apparent development of CSC, which is suppressed through the Zn
substitution oppositely, has been observed in non-superconducting heavily
overdoped samples, being argued in the context of a recently proposed
ferromagnetic state in heavily overdoped cuprates.Comment: 6 pages, 5 figure
On the Navier-Stokes equations with rotating effect and prescribed outflow velocity
We consider the equations of Navier-Stokes modeling viscous fluid flow past a
moving or rotating obstacle in subject to a prescribed velocity
condition at infinity. In contrast to previously known results, where the
prescribed velocity vector is assumed to be parallel to the axis of rotation,
in this paper we are interested in a general outflow velocity. In order to use
-techniques we introduce a new coordinate system, in which we obtain a
non-autonomous partial differential equation with an unbounded drift term. We
prove that the linearized problem in is solved by an evolution
system on for . For this we use
results about time-dependent Ornstein-Uhlenbeck operators. Finally, we prove,
for and initial data , the
existence of a unique mild solution to the full Navier-Stokes system.Comment: 18 pages, to appear in J. Math. Fluid Mech. (published online first
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