56 research outputs found
Structural disorder versus chiral magnetism in CrNbS
The crystal structure of a disordered form of CrNbS has been
characterized using diffraction and inelastic scattering of synchrotron
radiation. In contrast to the previously reported symmetry (P622), the
crystal can be described by a regular twinning of an average P6 structure
with three disordered positions of the Cr ions. Short-range correlations of the
occupational disorder result in a quite intense and structured diffuse
scattering; a static nature of the disorder was unambiguously attributed by the
inelastic x-ray scattering. The diffuse scattering has been modeled using a
reverse Monte-Carlo algorithm assuming a disorder of the Cr sub-lattice only.
The observed correlated disorder of the Cr sub-lattice reduces the temperature
of the magnetic ordering from 130 K to 88 K and drastically modifies the field
dependence of the magnetization as it is evidenced by the SQUID magnetometery.
We conclude, that in contrast to the helicoidal spin structure assumed for
P622 form, the compound under study is ferromagnetically ordered with a
pronounced in-plane anisotropy
Complex Chiral Modulations in FeGe close to Magnetic Ordering
We report on detailed polarized small-angle neutron scattering on cubic FeGe
in magnetic fields applied either along (transverse) the scattering vector or
parallel (longitudinal)to the neutron beam. The () phase diagrams for all
principal axes contain a segmented -phase region just below the onset of
magnetic order. Hexagonal Bragg-spot patterns were observed across the entire
-phase region for the longitudinal geometry. Scattering intensity was
observed in parts of the A phase for both scattering configurations. Only in a
distinct pocket () vanishing scattering intensity was found in the
transverse geometry.Comment: This paper has been withdrawn by the author due to misunderstanding
with some of the co-author
Chiral criticality in doped MnFeSi compounds
The critical spin fluctuations in doped compounds MnFeSi have
been studied by means of ac-susceptibility measurements, polarized neutron
small angle scattering and spin echo spectroscopy. It is shown that these
compounds undergo the transition from the paramagnetic to helimagnetic phase
through continuous, yet well distinguishable crossovers: (i) from paramagnetic
to partially chiral, (ii) from partially chiral to highly chiral fluctuating
state. The crossover points are identified on the basis of combined analysis of
the temperature dependence of ac-susceptibility and polarized SANS data. The
whole transition is marked by two inflection point of the temperature
dependence of ac-susceptibility: the upper one corresponds to the crossover to
partially chiral state at , where the inverse correlation length , the lower one corresponds to the transition to the spin helix
structure. The intermediate crossover to the highly chiral phase is observed at
the inflection point of the first derivative of ac-susceptibility, where
. The temperature crossovers to the highly chiral fluctuating
state is associated with the enhancing influence of the Dzyaloshinskii-Moria
interaction close to .Comment: 5 pages, 5 figures, 1 table, 13 cite
Toolkit for Simulation Modeling of Logistics Warehouse in Distributed Computing Environment
We address an important problem of an automation of logistics warehouses simulation modeling in distributed service-oriented computing environments. To this end, we propose new approach for adjusting management system parameters of real warehouse in production use. It is based on the integration of the conceptual, wireframe and service-oriented programming used to develop parameter sweep applications and data analysis in the simulation modeling process. We develop a toolkit for supporting modeling of warehouse logistics. The practical experiments are focused upon the refrigerated warehouse. The developed application demonstrates high efficiency and scalability for optimizing nine criteria to cope with different production demands.The study was supported by the Russian Foundation of Basic Research, projects no. 15-29-07955 and no. 16-07-00931, and Program 1.33P of fundamental research of Presidium RAS, project “Development of new approaches to creation and study of complex models of information-computational and dynamic systems with applications”
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