Search

Optically, unit sphere S2 is illustrated to be a 2-sphere in space with positive curvature. In this paper, we construct a new characterization for spherical electric and magnetic flow density of spherical Ss?magnetic flows of particles by the spherical frame in S2 spherical space. Thus, we get some new optical conditions of spherical Ss?magnetic electric and magnetic phase by using spherical magnetic fields. We determine spherical magnetic Lorentz flux for spherical vector fields. The results obtained show that q -HATM supplies an elementary algorithm to gain the approximated analytical solution. Finally, electric and magnetic phases of spherical surface are shown in uniform magnetic surfaces by using the analytical and fractional numerical results of the q-HATM algorithm. © 2021 Elsevier GmbH

Physically, unit sphere S 2 is illustrated to be a 2-sphere in space with a positive curvature. In this paper, we construct new characterization for spherical electric and magnetic flow density of spherical S t − m a g n e t i c flows of particles by the spherical frame in S 2 spherical space. Thus, we obtain some new optical conditions of spherical S t − m a g n e t i c electric and magnetic phase by using spherical magnetic fields. Moreover, we determine spherical magnetic Lorentz flux for spherical vector fields. Finally, electric and magnetic phase of spherical surface are demonstrated in uniform magnetic surface by using the analytical and fractional numerical results.

[EN] Dense multiferroic 0-3 type composites encompassing BaTiO and YFeO were fabricated by the solid-state reaction method. X-ray diffraction data combined with scanning electron microscopy imaging show virtual immiscibility between the two phases, with the YFeO ferrimagnetic phase well dispersed in the tetragonal BaTiO ferroelectric matrix. Raman spectroscopy analyses corroborate the polar nature of the BaTiO matrix in composites with a YFeO content as great as 40 wt%. Ferrimagnetism is detected in all composites and no additional magnetic phases are distinguished. Although these dense ceramics can be electrically poled, they exhibit a very weak magnetoelectric response, which slightly increases with YFeO content., This work was funded by the Christian Doppler Association in cooperation with TDK-EPC (Austria). LM acknowledges the grant PN-II-ID-PCE-2011-3-0745, while MA thanks funding by Spanish MINECO through project MAT2014-58816-R.

Collective electronic fluctuations in correlated materials give rise to various important phenomena, such as existence of the charge ordering, superconductivity, Mott insulating and magnetic phases, plasmon and magnon modes, and other interesting features of such systems. Unfortunately, description of these correlation effects requires significant efforts, since they almost entirely rely on strong local and nonlocal electron-electron interactions. Some collective phenomena, such as magnetism, can be sufficiently described by a simple Heisenberg-like models that are formulated in terms of bosonic variables. This fact suggests that other many-body excitations can also be described by simple bosonic models in spirit of the Heisenberg theory. Here we derive an effective bosonic action for charge degrees of freedom for the extended Hubbard model and define a physical regime where the obtained action reduces to a classical Hamiltonian of an effective Ising model.

Various auxiliary-particle approaches to treat electron correlations in many-electron models are analyzed. Applications to copper-oxide layered systems are discussed. The ground-state magnetic phase diagrams are considered within the Hubbard and $s$-$d$ exchange (Kondo) models for square and simple cubic lattices vs. band filling and interaction parameter. A generalized Hartree-Fock approximation is employed to treat commensurate ferro-, antiferromagnetic, and incommensurate (spiral) magnetic phases, and also magnetic phase separation. The correlations are taken into account within the Hubbard model by using the slave-boson approach. The main advantage of this approach is correct estimating the contribution of doubly occupied states number and therefore the paramagnetic phase energy., Physics of Metals and Metallography, special issue, 4 pages

Temperature variation of electrical resistivity, AC susceptibility and electron spin resonance measurements are reported for La0.67Ca0.33Mn0.93Fe0.07O3. The inverse of AC susceptibility shows a downturn with decreasing temperature before Tc indicating the existence of Griffiths phase for the temperature range Tc ≤ T ≤ TG, where TG is the Griffiths temperature. The ESR results show the existence of FM clusters in the PM region above Tc which supports the presence of Griffiths phase. The ESR results also show the existence of inhomogeneous distribution of magnetic phases in the sample. A possible mechanism of the obtained results has been explained.

The role of rare earth ion R3+ in spin reorientation and magneto dielectric response is investigated by substitution of non-magnetic smaller ionic radii Lu3+ in multiferroic hexagonal HoMnO3. The XRD analysis suggests that the dopant may preferably goes to C3V site up to 1/3rd of the composition in order to reduce the lattice distortion. We suggest that the R3+ ion at C3 site could play a strong role in spin reorientation than the C3V site. The observation of TSR even in LuMnO3 precludes the role of rare earth magnetic moment in driving the spin reorientation. Surprisingly, the magneto dielectric response of HoMnO3 is dominated by the rare earth RO 8 dipoles. The oppositely oriented RO8 dipole at the C3V and C3 determines the magneto dielectric response in various magnetic phases reaffirming the site specific substitution. Thus, site specific doping could be a way to enhance the magnetoelectric coupling strength. � 2013 AIP Publishing LLC.

Recently, bulk amorphous alloys were produced in the Fe–B–Si–P–C system with high glass forming ability, excellent magnetic properties and the advantage of containing no expensive glass-forming elements, such as Ga, Y, Cr or Nb, having, therefore, a good perspective of commercial applications. In the present work, the Fe76P5(Si0.3B0.5C0.2)19 amorphous alloy prepared by two quenching techniques has been studied. Amorphous ribbons of about 40 μm thick were obtained by planar-flow casting together with cylinders having 1 and 2 mm diameter produced by copper mold injection casting. All the samples appear fully amorphous after X-ray diffraction analysis. A comprehensive set of thermal data (glass, crystallization, melting and liquidus temperatures) were obtained as well as a description of the melting and solidification processes. Mechanical microhardness tests showed that the samples have a hardness of 9.7 ± 0.3 GPa. Good soft-magnetic properties were obtained, including a high magnetization of 1.44 T and a low coercivity (4.5 A/m for ribbons and 7.5 A/m in the case of 1 mm rod samples, both in as-cast state). Thermomagnetic studies showed a Curie temperature around 665 K and the precipitation of new magnetic phases upon temperatures of 1000 K. Furthermore, the frequency dependence of magnetic losses at a fixed peak induction was studied. The results suggest the occurrence of a fine magnetic domain structure in bulk samples. The good soft magnetic properties of the bulk metallic glass obtained by copper mold casting for this particular Fe-based composition suggests possible applications in transformer cores, inductive sensors and other devices. Fil: Lavorato, Gabriel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universita di Torino; Italia Fil: Fiore, G.. Universita di Torino; Italia Fil: Tiberto, P.. Istituto Nazionale di Ricerca Metrologica. Electromagnetism Division; Italia Fil: Baricco, M.. Universita di Torino; Italia Fil: Sirkin, Hugo Ricardo Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina Fil: Moya, J.A. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universidad Católica de Salta; Argentina

We report muon spin rotation and magnetization measurements under pressure on ${\mathrm{Fe}}_{1+\ensuremath{\delta}}{\mathrm{Se}}_{1\ensuremath{-}x}{\mathrm{S}}_{x}$ with $x\ensuremath{\approx}0.11$. Above $p\ensuremath{\approx}0.6\text{ }\text{ }\mathrm{GPa}$ we find a microscopic coexistence of superconductivity with an extended dome of long range magnetic order that spans a pressure range between previously reported separated magnetic phases. The magnetism initially competes on an atomic scale with the coexisting superconductivity leading to a local maximum and minimum of the superconducting ${T}_{c}(p)$. The maximum of ${T}_{c}$ corresponds to the onset of magnetism while the minimum coincides with the pressure of strongest competition. A shift of the maximum of ${T}_{c}(p)$ for a series of single crystals with $x$ up to 0.14 roughly extrapolates to a putative magnetic and superconducting state at ambient pressure for $x\ensuremath{\ge}0.2$.