4,561 research outputs found
M\"obius Symmetry of Discrete Time Soliton Equations
We have proposed, in our previous papers, a method to characterize integrable
discrete soliton equations. In this paper we generalize the method further and
obtain a -difference Toda equation, from which we can derive various
-difference soliton equations by reductions.Comment: 21 pages, 4 figure, epsfig.st
Spin Dynamical Properties of the Layered Perovskite La1.2Sr1.8Mn2O7
Inelastic neutron-scattering measurements were performed on a single crystal
of the layered colossal magnetoresistance (CMR) material La1.2Sr1.8Mn2O7 (Tc ~
120K). We found that the spin wave dispersion is almost perfectly
two-dimensional with the in-plane spin stiffness constant D ~ 151meVA. The
value is similar to that of similarly doped La1-xSrxMnO3 though its Tc is three
times higher, indicating a large renormalization due to low dimensionality.
There exist two branches due to a coupling between layers within a
double-layer. The out-of-plane coupling is about 30% of the in-plane coupling
though the Mn-O bond lengths are similar.Comment: 3 pages, 3 figures J. Phys. Chem. Solids in pres
A Characterization of Discrete Time Soliton Equations
We propose a method to characterize discrete time evolution equations, which
generalize discrete time soliton equations, including the -difference
Painlev\'e IV equations discussed recently by Kajiwara, Noumi and Yamada.Comment: 13 page
Manufacture of dense sintered bodies containing silicon nitride
Sintered bodies containing 1-32.5 Si oxide and 1.5 wt.% SiC (Si oxide/SiC wt. ratio 3/2) are prepared and kept in a 10-3000 kg/2 sq. cm. N (g) atmosphere at 1500-2300 degrees, while simultaneously maintaining the CO (g) partial pressure around the body lower than the nitrogenation equil. pressure to give a dense sintered body. The prepared dense sintered body has high strength at high temperatures. Thus, SiC 40, oxide 30 and Si3N4 30 wt% were fired to a body which was kept in 1500 kg/sq. cm. N (g) for 20 h at 2000 degrees to give a dense sintered body having high bending strength at high temperatures
A direct method for solving the generalized sine-Gordon equation II
The generalized sine-Gordon (sG) equation
was derived as an integrable generalization of the sG equation. In a previous
paper (Matsuno Y 2010 J. Phys. A: Math. Theor. {\bf 43} 105204) which is
referred to as I, we developed a systematic method for solving the generalized
sG equation with . Here, we address the equation with . By
solving the equation analytically, we find that the structure of solutions
differs substantially from that of the former equation. In particular, we show
that the equation exhibits kink and breather solutions and does not admit
multi-valued solutions like loop solitons as obtained in I. We also demonstrate
that the equation reduces to the short pulse and sG equations in appropriate
scaling limits. The limiting forms of the multisoliton solutions are also
presented. Last, we provide a recipe for deriving an infinite number of
conservation laws by using a novel B\"acklund transformation connecting
solutions of the sG and generalized sG equations.Comment: To appear in J. Phys. A: Math. Theor. The first part of this paper
has been published in J. Phys. A: Math. Theor. 43 (2010) 10520
Electric Control of Spin Helicity in a Magnetic Ferroelectric
Magnetic ferroelectrics or multiferroics, which are currently extensively
explored, may provide a good arena to realize a novel magnetoelectric function.
Here we demonstrate the genuine electric control of the spiral magnetic
structure in one of such magnetic ferroelectrics, TbMnO3. A spin-polarized
neutron scattering experiment clearly shows that the spin helicity, clockwise
or counter-clockwise, is controlled by the direction of spontaneous
polarization and hence by the polarity of the small cooling electric field.Comment: 4 pages, 3 figure
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