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961.
962.
We considered the Heisenberg model on the recursive lattices with multi-spin interaction in a strong magnetic field as an approximation of the two-dimensional kagome lattice, as well as hexagonal recursive lattices as an approximation of triangular lattice, for solid 3He. In a strong magnetic field it is possible to approximate the Heisenberg model with the Izing one. Using dynamic approach, we obtain exact recursion relations for partition functions. Diagrams of the magnetization versus external magnetic field with different spin-exchange parameters and temperatures are presented. Magnetization plateaux, bifurcation points, and doublings are obtained. 相似文献
963.
Karen B. Paul 《Central European Journal of Physics》2007,5(1):11-24
Fe(2 ML)/V(y ML) and interleaved Fe(2 ML)/V(y ML)/Fe(3 ML)/V(y ML) superlattice systems with spacer thicknesses, y, (4 ≤ y ≤ 17) were investigated macro-magnetically to estimate the coupling strength and the magnetoresistance in these materials,
and particularly in the antiferromagnetically coupled monolayers. The results from the magnetic and magnetoresistive measurements
indicate that adding one monolayer of Fe increases the antiferromagnetic coupling and the magnetoresistivity ratio from 0.0075
mJ/m2 at 20 K and 2 % at 10 K for Fe(2 ML)/V(y ML), to 0.05 mJ/m2 and 2.5 % for Fe(2 ML)/V(y ML)/Fe(3 ML)/V(y ML) at the same temperatures. Both systems exhibit in-plane magnetic and magnetoresistive isotropy, therefore the increase
of the conferred physical parameters is attributed mainly to the stresses at the interface as governing mechanisms over the
magnetoelastic forces.
相似文献
964.
P. Mason N. Marginean G. Montagnoli S. Beghini F. Scarlassara E. Farnea C. A. Ur A. Meroni A. M. Stefanini L. Corradi E. Fioretto I. V. Pokrovskiy B. Guiot A. Gadea J. J. Valiente-Dobón F. Della Vedova R. Orlandi E. Sahin D. R. Napoli L. Berti N. Toniolo S. Szilner M. Trotta M. Romoli M. La Commara D. Pierroutsakou M. Sandoli G. Pollarolo G. Benzoni 《The European physical journal. Special topics》2007,150(1):359-361
PRISMA is a magnetic
spectrometer installed at Laboratori Nazionali di Legnaro (Italy)
and designed for A=100–200, E=5–10 MeV-per-nucleon beams, and for
possible use with the proposed radioactive beam facility SPES. The
foremost features of the instrument are presented, along with the
outline of two data analyses exemplifying the effectiveness of
PRISMA-CLARA in studies of reaction
dynamics. 相似文献
965.
R. M. Movsessyan A. S. Sahakyan M. A. Chalabyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2007,42(6):268-270
The scattering of nonspin-polarized electrons on a heterostructure containing a magnetic element (a nonmagnetic barrier adjoining a magnetic one from left or right, or a magnetic well between two nonmagnetic barriers) is considered. The transmission coefficients and degrees of the spin polarization of electrons transmitted through these structures are obtained. 相似文献
966.
967.
Ming Wen Kejia E Haiquan Qi Lujiang Li Juan Chen Ying Chen Qingsheng Wu Tao Zhang 《Journal of nanoparticle research》2007,9(5):909-917
Dispersed-well FePt nanoparticles with particle size ~5 nm have been prepared by hydrazine hydrate reduction of H2PtCl6·6H2O and FeCl2·4H2O in ethanol–water system. By employing as-synthesized FePt nanoparticles, the monolayer can be formed by LB Technique. The
structural, magnetic properties and electrochemical properties of FePt monolayer were respectively studied by XRD, TEM, VSM
and CHI 820 electrochemical workstation. The as-synthesized particle has a chemically disordered fcc structure and can be
transformed into chemically ordered fct structure after annealing treatment above 400°C. The coercivity of ordered fct FePt
phase can be up to 2515Oe. CVs of 0.5 M H2SO4/0.5M CH3OH on GCE modified with FePt nanoparticles monolayer films illustrate that the as-synthesized FePt is a kind of active electrochemical
catalyst. 相似文献
968.
B. Pedrini S. Wessel J. L. Gavilano H. R. Ott S. M. Kazakov J. Karpinski 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):219-228
We report results of susceptibility χ and 7Li NMR measurements on LiVSi2O6. The temperature dependence of the magnetic susceptibility χ(T) exhibits a broad maximum, typical for low-dimensional magnetic
systems. Quantitatively it is in agreement with the expectation for an S=1 spin chain, represented by the structural arrangement
of V ions.
The NMR results indicate antiferromagnetic ordering below TN=24 K. The intra- and interchain coupling J and Jp for LiVSi2O6, and also for its sister compounds LiVGe2O6, NaVSi2O6 and NaVGe2O6, are obtained via a modified random phase approximation which takes into account results of quantum Monte Carlo calculations.
While Jp is almost constant across the series, J varies by a factor of 5, decreasing with increasing lattice constant along the chain
direction. The comparison between experimental and theoretical susceptibility data suggests the presence of an easy-axis magnetic
anisotropy, which explains the formation of an energy gap in the magnetic excitation spectrum below TN, indicated by the variation of the NMR spin-lattice relaxation rate at T≪TN. 相似文献
969.
The structural stability and magnetic properties of the icosahedral Ni13, Ni13^+1 and Ni13^-1 clusters have been obtained by utilizing all-electron density functional theory with the generalized gradient approximations for the exchange-correlation energy. The calculated results show that the ground states of neutral and charged clusters all favour a D3d structure, a distorted icosahedron, due to the Jahn-Teller effect. The radial distortions caused by doping one electron and by doping one hole are opposite to each other. Doping one electron will result in a 1/2 decrease and doping one hole will result in a 1/2 increase of the total spin. Both increasing interatomic spacing and decreasing coordination will lead to an enhancement of the spin magnetic moments for Nil3 clusters. 相似文献
970.