Spin-one Research Articles

Electron and spin transport in adiabatic quantum pumps based on graphene nanoribbons

The adiabatic quantum pump effect in double-barrier structures based on graphene nanoribbons has been analyzed numerically. The charge transmitted through the system in one cycle of variation of pumping potentials (barrier heights) has been calculated. This charge is shown to be quantized under certain conditions. The possibility of the generation of not only electron currents but also spin and purely spin ones is considered. In devices based on zigzag nanoribbons, the spin current emerges when taking into account their magnetic structure and applying a transverse electric field breaking the symmetry between the up and down spins. In devices based on armchair nanoribbons without any magnetic structure, this symmetry breaks when using a ferromagnetic insulator (deposited, for example, on the region between gates) through the proximity effect.

Clinical conundrum

A 4-year-old Italian Spinone presented with a history of recurrent bilateral otitis externa, starting at 4 month of age. The diagnosis and treatment of atopic dermatitis complicated by Pseudomonas infection are described.

Electronic structure of dichloro-bridged ruthenium(II) dimers

Multiple-scattering X αβ-spin polarized calculations on clusters have been performed to establish a pattern of stability and electronic structure of this kind of dimer with atomic bridging species. In both cases the ground state had high spin, as did transition metal diatomics as found by Harris and Jones. Nevertheless, this causes a completely occupied set of majority spin orbitals and an incompletely filled group of minority spin ones with nonbonding d-metal character. As a result, a slightly bound dimer results from two monomers. From this result, and the fact that synthesized Ru(II) dimers are diamagnetic, it is concluded that stable halogen-bridged dimers would be obtained only if σ-electron-donating soft ligands and/or π-high-acceptor ones are attached to the metal center.

Pseudo-Unitary Conformal Spin Structures

Covering groups of the conformal pseudo-unitary groups are given. Conformal flat pseudo-unitary geometry is studied. Two fundamental diagrams are given. We introduce and give geometrical characterizations of groups called pseudo-unitary conformal spinoriality groups. The study of pseudo-unitary spin structures and conformal pseudo-unitary spin structures over an almost complex 2n-dimensional manifold V is now presented. The part played by groups called pseudo-unitary conformal groups is emphasized. The links between pseudo-unitary spin structures and pseudo-unitary conformal spin ones are given.

Matrix “blues”: clue to a cranial thoracic mass in a dog

A 5-year-old, intact male Italian Spinone dog was presented for progressive, severe dyspnea and coughing. Thoracic radiographs revealed a large mass in the right cranial thorax. Fine needle aspiration of the mass yielded a highly cellular sample containing dense clumps of oval to spindle-shaped mesenchymal cells with distinct intracytoplasmic vacuolation, consistent with lipoblasts and lipocytes. Cell clusters were associated with abundant eosinophilic matrix, which was identified as mucin, based on Alcian blue staining. At exploratory thoracotomy, the mass was found to be nonresectable, and the dog was euthanized. Histologic sections of the multilobular mass had discrete regions of variable cellular differentiation, including highly cellular areas of pleomorphic cells, areas of spindle cells and lipoblasts in a myxoid background, and areas of well-differentiated lipogenic cells. The histologic diagnosis was myxoid liposarcoma. The thoracic cavity is a rare site for liposarcoma in the dog. The cytologic features of lipoblasts together with a mucopolysaccharide matrix were useful for distinguishing the myxoid variant of liposarcoma from other forms of liposarcoma and myxoid sarcomas.

Spin and lattice configurationsin p‐conjugated organic ferromagnetic polymerwith open boundary condition

AbstractBy employing the extended Su–Schrieffer–Heeger Hamiltonian including on‐site and inter‐site Coulomb repulsions, we investigate the spin and lattice configurations in π‐conjugated organic ferromagnetic polymer under the open boundary condition. The results display that for a certain on‐site Coulomb repulsion, the domain solitons in varying appearances will successively appear along the main chain with increasing of electron–phonon interaction while the spin ones come into view at the side radicals, and, moreover, the inter‐site Coulomb repulsion will exert a great influence on both kinds of solitons.

Magnetic and Mössbauer Investigations of CoGa2-xFexO4

The magnetic properties of system CoGa 2-x Fe x O 4 (x=0.1, 0.2, 0.3, 04, 0.5., 0.8, 1) with spinel structure were investigated by means of dc susceptibility and dc magnetization measurements in magnetic fields 1-12kOe as well as by means of Mossbauer effect. The results of magnetic measurements show that compounds with 0.1 ≤ x ≤ 0.5 exhibit features typical for spin glasses and ones with x=0.8 and 1 have a ferromagnetic ordering. The compounds with x=0.8 and 1 exhibit relaxation behaviour in their Mossbauer spectra.

Inclusive transverse response of nuclear matter

The electromagnetic inclusive transverse response of nuclear matter at saturation density is studied within the correlated basis function perturbation theory for momentum transfers $q$ from $300$ to 550 MeV/$c$. The correlation operator includes a Jastrow component, accounting for the short range repulsion, as well as longer range spin, tensor, and isospin ones. Up to correlated one-particle--one-hole intermediate states are considered. The spreading due to the decay of particle (hole) states into two-particle--one-hole (two-hole--one-particle) states is considered via a realistic optical potential model. The Schiavilla-Pandharipande-Riska model for the two-body electromagnetic currents, constructed so as to satisfy the continuity equation with realistic ${v}_{14}$ potentials, is adopted. Currents due to intermediate $\ensuremath{\Delta}$-isobar excitations are also included. The global contribution of the two-body currents turns out to be positive and provides an enhancement of the one-body transverse response ranging from $\ensuremath{\sim}20%$ for the lower momenta to $\ensuremath{\sim}10%$ for the higher ones. This finding is in agreement with the Green's function Monte Carlo studies of the transverse Euclidean response in $A=3,4$ nuclei and contradicts previous results obtained within the Fermi gas and shell models. The tensor-isospin component of the correlation is found to be the leading factor responsible for such a behavior. The nuclear matter response is compared to recent experimental data on ${}^{40}$Ca and ${}^{56}$Fe.

Elastic and inelastic tunneling between a high- Tc oxide and normal metal

Considering the weakening effect of the strong correlation in high- T c materials on the electron transition probabilities in the tunneling hamiltonian introduced by Kirtley et al., we obtained an elastic tunneling term in addition to their inelastic one. The elastic term results from the density of state effects, and produces a constant background to the differential conductance even at zero temperature. The constant is directly proportional to the doped hole concentration. Charge fluctuations also turned out to contribute to the inelastic tunneling just as the spin ones. Treating the charge and spin fluctuations on the same footing, we show that the total differential conductance still has a V-shape behavior on the constant background as observed experimentally.

Hereditary problems in Italian spinones

Hereditary problems in Italian spinones

Magnetic circular dichroism and spin equilibrium of methemoglobin and its subunits

The intensity of the Soret magnetic circular dichroism (MCD) spectra of various complexes of methemoglobin subunits (α + and β +) as well as methemoglobin (metHb A) was correlated well with the spin states of ferric heme. Upon the subunit association, spin state transition toward higher spin was observed only in high spin derivatives and the changes in spin state were due to mainly those of β + chains. The effect of an allostric effector, inositol hexaphosphate (IHP), on the MCD spectra of metHb A derivatives was observed much significantly for high spin forms than low spin ones.

A treatment of spin-one polarization

A treatment of spin-one polarization

Study of variation in properties of ferric porphyrins with fifth ligands—magnetic hyperfine interactions

The electronic structures and magnetic hyperfine interactions in a series of related heme compounds have been studied. Four of these are high spin ferric heme compounds with different fifth ligands, namely, fluoride, chloride, bromide, and hydroxide, and the fifith is a low spin cyano–ferric–heme compound. The molecular orbitals needed in the calculation were obtained by the self-consistent charge extended Hückel method. For the four high spin ferric compounds the hyperfine constants of 57Fe and 14N nuclei were found to vary only 4% among themselves. In the chloride derivative, the only one for which 57Fe data are available, excellent agreement was found between our result and the 57Fe hyperfine field in hemin from Mössbauer measurements. For 14N nuclei in the fluoride, chloride, and bromide derivatives the near constancy of the predicted hyperfine constants is borne out experimentally, with the theoretical values being all about 50% of experiment. For the low-spin cyano compound we predict the 57Fe hyperfine field per spin to be 60% larger than the corresponding fields in high spin heme derivatives, while the hyperfine field at 14N per spin is substantially smaller than its counterpart in the high spin compounds. Our results for the hyperfine fields in the series of compounds studied and their agreement with available experimental data demonstrate that there is substantial delocalization of unpaired spin away from iron for these ferric heme compounds, especially the high spin ones. This feature is also supported by a similar calculated decrease in the iron 3s core energy splittings relative to that expected in free Fe+3 ion, which is verified by ESCA measurements in hemin chloride. The need for additional experimental data on the hyperfine fields, particularly for 57Fe and 14N in the cyano compound, is stressed.

Eigenproblem solution of damped structural systems

AbstractThis article presents an efficient numerical algorithm a complete listing of the associated computer program, developed for the eigenproblem solution of discrete damped structures, including spinning ones. The numerically stable procedure is based on a combined Sturm sequence and inverse iteration technique, which fully exploits the banded form of the relevant matrices and proves to be most substantially economical when compared to similar existing softwares. Numerical results are presented for representative structures, solved by the present computer program written in FORTRAN V for the JPL UNIVAC 1108 computer.