362 research outputs found
Educational ecosystem in conditions of digital transformation
Currently, there is an active digital transformation of management practices and processes in the world, associated with the emergence of an ecosystem approach. The ecosystem approach is being actively implemented in all spheres of the economy and society. This phenomenon has not bypassed the education sphere. The article considers the priority tasks and trends in the development of education that meet the global challenges of the changing world economy, and aimed at developing a new paradigm of training throughout life. The purpose of the study is to analyze the factors influencing the creation of an educational ecosystem of the future, designed to form and develop a culture of lifelong learning, and, consequently, to the need for the introduction of network models based on elements of joint and voluntary learning. The research methods are comparative and causal analysis of management decisions. As a result of the study, the authors identify the elements of the educational and personnel ecosystems that affect the business processes of an organization in the context of digital transformation. It will significantly accelerate the possibilities of cooperation between the real sector of the economy, the educational ecosystem and the state within the framework of the above changes. The ecosystem transformation of education will allow to educate a new generation that will lead the transition to the effective and harmonious development of world civilization. The ecosystem approach will change the traditional ways of learning, discovering, acting on the principles of cooperation. These changes are aimed at dialogue in terms of business training in the conditions of digitalisation of the economy between the educational ecosystem and the business environment. Therefore, it is the personnel service for business processes that should be given increased attention to representatives of the real sector of the economy, the scientific community and educational institutions
Structural and magnetic dimers in the spin-gapped system CuTe2O5
We investigated the magnetic properties of the system CuTe2O5 by
susceptibility and electron spin resonance measurements. The anisotropy of the
effective g-factors and the ESR linewidth indicates that the anticipated
structural dimer does not correspond to the singlet-forming magnetic dimer.
Moreover, the spin susceptibility of CuTe2O5 can only be described by taking
into account interdimer interactions of the same order of magnitude than the
intradimer coupling. Analyzing the exchange couplings in the system we identify
the strongest magnetic coupling between two Cu ions to be mediated by
super-super exchange interaction via a bridging Te ligand, while the
superexchange coupling between the Cu ions of the structural dimer only results
in the second strongest coupling
Singlet-triplet excitations and high-field magnetization in CuTe2O5
By measuring the THz electron spin resonance (ESR) transmission spectra and
high-field magnetization on the spin-gapped system CuTeO, we identified
the singlet-triplet excitations in the dimerized non-magnetic ground state. The
determined spin-gap value of meV at the point
() is significantly smaller than the strongest
antiferromagnetic exchange interaction between the Cu ions predicted by
theoretical investigations. We also observed the critical field
T for \textbf{H} \emph{bc}-plane and
T for \textbf{H} \emph{bc}-plane at the onset of
non-zero magnetization, consistent with the gap value and corresponding
anisotropic \emph{g}-factors determined previously. The observed
singlet-triplet excitations in Faraday and Voigt configurations suggest a
mixing of the singlet state with the triplet state and the
triplet states, respectively, due to the Dzyaloshinskii-Moriya (DM) interaction
with a DM vector perpendicular to the crystalline \emph{bc}-plane.Comment: 5 pages, 4 figure
Observation of a Griffiths phase in paramagnetic La1-xSrxMnO3
We report on the discovery of a novel triangular phase regime in the system La1-xSrxMnO3 by means of electron spin resonance and magnetic susceptibility measurements. This phase is characterized by the coexistence of ferromagnetic entities within the globally paramagnetic phase far above the magnetic ordering temperature. The nature of this phase can be understood in terms of Griffiths singularities arising due to the presence of correlated quenched disorder in the orthorhombic phase
Anisotropic exchange interactions in CuTe2O5
Electron paramagnetic resonance (EPR) was used to study CuTe 2O5 single crystals at frequencies of 9.4 and 160 GHz. Analytic expressions for the second and fourth moments of the EPR line are deduced with inclusion of the difference between the exchange couplings of the copper spin with its different neighbors. From comparing the calculated and measured EPR linewidths, the positions of copper ions with the strongest exchange interactions are identified. The parameters of the anisotropic exchange interaction between copper ions in a pair are found. The parameter of the exchange interaction between magnetically nonequivalent copper centers is determined from the frequency dependence of the EPR linewidth. The directions of the principal axes of the g tensors are established. The data obtained count in favor of a quasi-one-dimensional model of magnetism in CuTe2O 5. © 2008 Pleiades Publishing, Ltd
Electron-spin-resonance in the doped spin-Peierls compound Cu(1-x)Ni(x)GeO3
ESR-study of the Ni-doped spin-Peierls compound CuGeO3 has been performed in
the frequency range 9-75 GHz. At low temperatures the g-factor is smaller than
the value expected for Cu- and Ni-ions. This anomaly is explained by the
formation of magnetic clusters around the Ni-ions within a nonmagnetic
spin-Peierls matrix. The transition into the AFM-state detected earlier by
neutron scattering for doped samples was studied by means of ESR. For x=0.032 a
gap in the magnetic resonance spectrum is found below the Neel temperature and
the spectrum is well described by the theory of antiferromagnetic resonance
based on the molecular field approximation. For x=0.017 the spectrum below the
Neel point remained gapless. The gapless spectrum of the antiferromagnetic
state in weekly doped samples is attributed to the small value of the Neel
order parameter and to the magnetically disordered spin-Peierls background.Comment: 16 pages, LATEX, 12 figures, submitted to Journal of Physics :
Condensed Matte
Crystal Field and Dzyaloshinsky-Moriya Interaction in orbitally ordered La_{0.95}Sr_{0.05}MnO_3: An ESR Study
We present a comprehensive analysis of Dzyaloshinsky-Moriya interaction and
crystal-field parameters using the angular dependence of the paramagnetic
resonance shift and linewidth in single crystals of La_{0.95}Sr_{0.05}MnO_3
within the orthorhombic Jahn-Teller distorted phase. The Dzyaloshinsky-Moriya
interaction (~ 1K) results from the tilting of the MnO_6 octahedra against each
other. The crystal-field parameters D and E are found to be of comparable
magnitude (~ 1K) with D ~= -E. This indicates a strong mixing of the |3z^2-r^2>
and |x^2-y^2> states for the real orbital configuration.Comment: 12 pages, 6 figure
Magnetic properties of (La<inf>0.7</inf>Sr<inf>0.3</inf>MnO<inf>3</inf>)<inf>x</inf>(CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf>)<inf>1−x</inf>nanostructured composites
© 2017 Elsevier B.V. (La 0.7 Sr 0.3 MnO 3 ) x (CaCu 3 Ti 4 O 12 ) 1−x (0.01 ≤ x ≤ 0.3) nanostructured composites with La 0.7 Sr 0.3 MnO 3 (LSMO) microinclusions in CaCu 3 Ti 4 O 12 (CCTO) matrix were synthesized using a solid state method. The structural and microstructural details were studied by X-ray diffraction (XRD), X-ray fluorescence (XFA), scaning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The magnetic properties were studied by electron spin resonance (ESR) and magnetometry methods. In the concentration range 0.01 <  x <  0.1 physical properties of composites differ from the properties of the individual components CCTO or LSMO. The Curie temperature of the ferromagnetic phase for all concentrations is T C  = 315 K, that is less at 50 K than in pure LSMO. The Weiss constant of the paramagnetic phase has the strong concentration dependance. The observed mutual influence on the magnetic properties of both components can be tentatively attributed to the interface exchange interactions between them, hinting a possible magnetic proximity effect
Anisotropic exchange in LiCu2 O2
© 2017 American Physical Society. We investigate the magnetic properties of the multiferroic quantum-spin system LiCu2O2 by electron spin resonance (ESR) measurements at X- and Q-band frequencies in a wide temperature range (TN1≤T≤300 K). The observed anisotropies of the g tensor and the ESR linewidth in untwinned single crystals result from the crystal-electric field and from local exchange geometries acting on the magnetic Cu2+ ions in the zigzag-ladder-like structure of LiCu2O2. Supported by a microscopic analysis of the exchange paths involved, we show that both the symmetric anisotropic exchange interaction and the antisymmetric Dzyaloshinskii-Moriya interaction provide the dominant spin-spin relaxation channels in this material
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