133 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transverse geometry.Comment: This paper has been withdrawn by the author due to misunderstanding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
JURISOMETRICS
Matters of new methodology in jurisprudence based on modern mathematical methods are presented in the article. The author offers the basis of a new science – jurisometrics. It can become an integral part of the modern legal decision-making support system of not only law enforcement, but also lawmaking nature
Preliminary observations of the interplay of radiation damage with spin crossover
Intense synchrotron radiation makes time-resolved structural experiments with increasingly finer time sampling possible. On the other hand, radiation heating, radiation-induced volume change and structural disorder become more frequent. Temperature, volume change and disorder are known to be coupled with equilibrium in molecular spin complexes, balancing between two or more spin state configurations. Combining single-crystal diffraction and synchrotron radiation it is illustrated how the radiation damage and associated effects can affect the spin crossover process and may serve as yet another tool to further manipulate the spin crossover properties.publishedVersio
LEGAL MEANS OF ENSURING PUBLIC SAFETY AS A BASIS FOR THE PROGRESSIVE DEVELOPMENT OF SOCIETY
Objective: The article investigates the key areas to improve the effectiveness of legal means for human rights protection in the conditions of spreading ideology that promotes the development of extremist and terrorist activities. Methods: Close attention is paid to the scale of spreading extremism and terrorism ideology at transnational, interstate and national levels. Results: The focus of activity in terrorist organizations is emphasized on destruction or disruption of transport infrastructure, life support facilities, intimidation of population and committing acts of nuclear terrorism. Conclusions: It is necessary to develop a legal policy that promotes the implementation of measures to protect human rights, regardless to the nature of the political and legal system in the state. The universality of measures for the protection of human rights implies their viability in various socially interactive legal systems. The necessity to develop new approaches to justify the formation of ideology of terrorism and extremism is determined. Attention is paid to the necessity to improve legal grounds for understanding terrorism and extremism
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
Crystal structures of cristobalite-type and coesite-type PON redetermined on the basis of single-crystal X-ray diffraction data
Hitherto, phosphorus oxonitride (PON) could not be obtained in the form of single crystals and only powder diffraction experiments were feasible for structure studies. In the present work we have synthesized two polymorphs of phosphorus oxonitride, cristobalite-type (cri-PON) and coesite-type (coe-PON), in the form of single crystals and reinvestigated their crystal structures by means of in house and synchrotron single-crystal X-ray diffraction. The crystal structures of cri-PON and coe-PON are built from PO2N2 tetrahedral units, each with a statistical distribution of oxygen and nitrogen atoms. The crystal structure of the coe-PON phase has the space group C2/c with seven atomic sites in the asymmetric unit [two P and three (N,O) sites on general positions, one (N,O) site on an inversion centre and one (N,O) site on a twofold rotation axis], while the cri-PON phase possesses tetragonal I-42d symmetry with two independent atoms in the asymmetric unit [the P atom on a fourfold inversion axis and the (N,O) site on a twofold rotation axis]. In comparison with previous structure determinations from powder data, all atoms were refined with anisotropic displacement parameters, leading to higher precision in terms of bond lengths and angles
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