Papers by Keyword: Magnetic Moment

Abstract: Density-functional-theory calculations have been performed to investigate the magnetism induced in silicene and germanene by hydrogen terminations. We varied the H-terminated structures from monomers to pentamers. Silicene and germanene exhibit magnetic properties after H termination, as indicated by the appearance of magnetic moments. The greater the magnetic moment, the more H atoms are added in the same direction. Conversely, H atoms added in the opposite direction reduce the magnetic moment. We calculated the adsorption energy for each variation of H-terminated silicene and germanene. The results show that both have negative adsorption energies. H-terminated silicene has a more negative adsorption energy than H-terminated germanene. For example, pentamer silicene has an adsorption energy of -10.37 eV, while pentamer germanene has an adsorption energy of -7.39 eV. This indicates that H is more easily adsorbed on silicene. Thus, H-terminated silicene and germanene are suitable for magnetic material device applications.

Abstract: We have investigated the magnetism and superconductivity of the electron-doped Eu_2-xCe_xCuO_4+α-δ in a wide range area of doping Ce⁴⁺ at 0.09 ≤ x ≤ 0.20 by means of magnetic susceptibility measurement at low temperatures down to 2 K. Superconductivity was observed in the concentration of Ce⁴⁺ at 0.12 ≤ x ≤ 0.20 with the range of the reduction of oxygen content 0.0255 ≤ δ ≤ 0.093 with a maximum transition temperature of 12 K. Furthermore, from the data temperature dependence of the dc magnetic-susceptibility, it can be analyzed the Curie constant, atomic magnetic moment and effective magnetic moment in each sample. Those three values have similar values with increasing Ce⁴⁺ concentration for a sample that doesn’t show superconductivity.

Abstract: The electronic and magnetic properties of palladium hydrogen are investigated using first-principles spin-polarized density functional theory. By studying the magnetic moments and electronic structures of hydrogen atoms diffusing in face-centered cubic structure of transition metal Pd, we found that the results of magnetic moments are exactly the same in the two direct octahedral interstitial site-octahedral interstitial site diffusion paths-i.e. the magnetic moments are the largest in the octahedral interstitial site, and the magnetic moments are the lowest in saddle point positions. We also studied on the density of states of some special points, with the result that the density of states near the Fermi level is mainly contributed by 4d electrons of Pd and the change of magnetic moments with the cell volume in the unit cell of transition metal Pd with a hydrogen atom.

Abstract: Ferrite with mixed complex oxides BiNaFe₂O₅, BiKFe₂O₅ was synthesized by high temperature solid state reaction. The structure of the ferrites, type of syngony, parameters of the unit cells, radiographic and pycnometric densities were determined by X-ray phase analysis for a first time: BiNaFe₂O₅ – а=5,577, с=13,86 Å, γ=120º, Vun.cell. = 373,9 Å3, Z=4, ρrad.= 7,5262 г/см³, ρpicn.=7,5271 г/см3, BiKFe₂O₅ –а=5,545, с=13,65 Å, γ=120º, Vun.cell.= 363,45Å3, Z=6, ρrad.= 8,0367, ρpicn.=8,0375 г/см³. A comparative analysis of the relationship between crystal lattice parameters with parameters of the crystal lattice of initial oxides and complex ferrites has been performed. Research dependence of the magnetic moment of the complex ferrite BiNaFe₂O₅ of the applied magnetic field at a constant temperature T = 6.1405 K showed a paramagnetic shift in the structure.

Abstract: Temperature dependence of the low-frequency complex magnetic susceptibility of magnetic colloid with paraffin as a dispersion medium has been studied. When interpreting the obtained results, the specific features of the magnetic moment relaxation of single-domain particles and the possibility of changing of relaxation mechanism from Neel to Brownian have been considered.

Abstract: The optical properties of colloidal solutions of nanosized magnetite particles in kerosene were studied by optical methods (birefringence and light scattering). The data on the birefringence kinetics in nonstationary magnetic fields is used to determine the size distribution of magnetite particles and aggregates. It is shown that the particle size distribution essentially depends on the type of magnetic moments of the particles and aggregates. Static and dynamic light scattering experiments confirm the conclusion about the existence of a significant fraction of nanoparticles in the form of aggregates with sizes of several tens of nanometers.

Abstract: The Bi₂(Sn_0.95Mn_0.05)₂O₇ compound existing simultaneously in two polymorphic modifications, namely, orthorhombic and cubic has been synthesized for the first time by solid-phase synthesis. The magnetic, dielectric and electrical properties of the compound have been studied. Anomalies in the temperature dependences of the electrical resistance and magnetic propoties have been found. These features are explained as martensitic phase transitions.

Abstract: This paper presents the investigation of the probability of changes in the magnetic properties of nanomaterials in strong fields of charged particles, neutrons and gamma rays. Co_xNi_1-xFe₂O₄ nanoparticles were obtained by the hydrothermal method using polyethylene glycol. Investigation of the properties of this material showed that its magnetic properties depend on the concentration of Со²⁺. In this work it is shown that the nuclear reactions taking place in the crystal lattice sites can change the relative concentration of the components of test material and, accordingly, its magnetic properties, including the coercive force.

Abstract: The bond length, average binding energy, magnetic moment per atom and the ionic potential of Ni_n (2-13) clusters were calculated in detail. The variations of magnetic moment per atom and the ionic potential agree well with experimental data. Theoretical results show that BPW91/Lanl2dz method is the best method and basis set for nickel clusters research, respectively. The ground state configurations and electronic structure properties of Ni_n (2-13) clusters were investigated using the BPW91/LanL2DZ level of DFT method. Through the molecular orbital, we could explain the paramagnetic and diamagnetic to the influence of the magnetic moment after different nickel cluster molecular hybridization.

Abstract: In this paper we research the process of magnetization of iron-containing coatings obtained on aluminum and titanium plasma electrolytic oxidation. It is shown that the formation of a remnant magnetic moment mainly determined by the magnetostatic interaction particles (phases). This interaction leads to a decrease of the blocking volume of particles (phases). Thus, a large number of superparamagnetic particles (phases) obtain stable magnetic moments and are involved in creating of the remnant magnetization of the sample.