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71.
The structures of the carbon sublayers in the annealed Co/C soft X-ray multilayers fabricated by using a dual-facing-target
sputtering system have been characterized by transmission electron microscopy (TEM) and Raman spectroscopy (RS). The results
suggest that the structural variations in the carbon layers can be roughly divided into three stages, i.e. ordering, crystalline
and grain growth stages. At the ordering stage with annealing temperatures below 400°C, the amorphous carbon layers change
from ones of bond-angle disorder and fourfold-bonding only to ones of threefold-bonding. At the crystalline stage, the amorphous
carbon layers in the as-deposited multilayers crystallize to graphite crystallites in the annealing temperature range of 500–600°C.
At the grain growth stage, the specimens are annealed at temperatures higher than 700°C. A growth in the graphite crystallite
dimensions is observed, which is consistent with the TEM results.
Project supported by the National Natural Science Foundation of China and Beijing Zhongguancun Associated Center of Analysis
and Measurement. 相似文献
72.
Thin Co/Fe multilayers were e-beam evaporated in ultra-high vacuum, keeping constant the Co layer thickness and varying that
of Fe in the 0.5÷15 nm range. By increasing the Fe layer thickness, a component of magnetization perpendicular to the film
plane rises up, and long and parallel magnetic domains (stripe domains) appear. The phenomenon is explained on the basis of
the competition between the magnetoelastic anisotropy induced by stresses at the interfaces, and the shape anisotropy constraining
the magnetization in the film plane.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
73.
74.
Co2FeAl0.5Si0.5 (CFAS)-based multilayers sandwiched by MgO layers have been deposited and annealed at different temperatures. Perpendicular magnetic anisotropy (PMA) with the magnetic anisotropy energy density Ku ≈2.5×106 erg/cm3 (1 erg = 10-7 J) and the coercivity Hc = 363 Oe (1 Oe = 79.9775 A · m-1) has been achieved in the Si/SiO2/MgO (1.5 nm)/CFAS (2.5 nm)/MgO (0.8 nm)/Pt (5 nm) film annealed at 300 ℃. The strong PMA is mainly due to the top MgO layer. The structure can be used as top magnetic electrodes in half-metallic perpendicular magnetic tunnel junctions. 相似文献
75.
M. Belhadi O. Rafil R. Tigrine A. Khater J. Hardy A. Virlouvet K. Maschke 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(3):435-443
The influence of linear defect boundaries on the transmission and scattering of elastic waves in quasi-two-dimensional wave-guides
is studied using the matching method. A linear defect boundary separating two wave-guide crystalline lattice domains is characterised
here by a linear chain of defect masses and by modified elastic constants in the boundary, different from their values in
the bulk of the domains. In particular a square lattice is considered to model the domains of the two-dimensional planar wave-guide
containing the linear defect. The reflection and transmission probabilities, and the total transmission probabilities are
calculated numerically and presented for the scattering processes in a variety of cases. We show that the interaction between
the localised modes introduced by the defect boundary and the propagating modes of the system leads to Fano resonances. These
resonances shift to higher (lower) frequencies for smaller (larger) defect masses, and for the same mass as function of the
angle of the incident wave. Other spectral features shown to exist are due to interference effects especially at oblique incidence
and when modifying the boundary elastic constants.
Received 8 November 1999 and Received in final form 14 January 2000 相似文献
76.
Resonance split of ballistic conductance peaks in electric and magnetic superlattices 总被引:1,自引:0,他引:1
Z.Y. Zeng L.D. Zhang 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(3):389-392
Resonant peak splitting for ballistic conductance in finite electric superlattices (ES) and magnetic superlattices (MS) was
investigated theoretically. It is shown that, for electron tunneling through the ES (MS) of identical n electric (magnetic) barriers, the resonance split of the conductance peak is (n–1)-fold; while for electron tunneling through the ES (MS) made of two different barriers, one resonant window of the former
splits into two subwindows, within each of which the resonance split is (m–1)-fold, where m is the number of the renormalized building blocks consisting of two different barriers of the latter.
Received 15 February 2000 相似文献
77.
U. Pustogowa C. Blaas C. Uiberacker J. Zabloudil P. Weinberger L. Szunyogh C. Sommers 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(4):653-658
The magnetic properties of (ConPdm)r superstructures on Pd(100) and Pd(111) are evaluated using the fully-relativistic spin-polarized screened Korringa-Kohn-Rostoker
method. It is found that only in the case of a Pd(111) substrate such superstructures exhibit perpendicular magnetism, while
on a Pd(100) substrate the magnetization is oriented in-plane. Also investigated is the effect of interdiffusion in repeated
superstructures. By using the inhomogeneous coherent potential approximation (CPA) for layered systems the effect of ordering
into (repeated) superstructures can be described in an ab-initio-like manner. It is found that already small amounts of interdiffusion can be decisive for the actual value of the magnetic
anisotropy energy.
Received 3 November 1999 and Received in final form 18 January 2000 相似文献
78.
L. Sheng H.Y. Teng D.Y. Xing 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,10(2):209-213
Using the two-point conductivity formula, we numerically evaluate the giant magnetoresistance (GMR) in magnetic superlattices
with currents in the plane of the layers (CIP), from which the effect of the interfacial roughness and magnetization configuration
on the GMR is studied. With increasing interfacial roughness, the maximal GMR ratio is found to first increase and then decrease,
exhibiting a peak at an optimum strength of interfacial roughness. For systems composed of relatively thick layers, the GMR
is approximately proportional to ,where is the angle between the magnetizations in two successive ferromagnetic layers, but noticeable departures from this dependence
are found when the layers become sufficiently thin.
Received 21 September 1998 and Received in final form 22 December 1998 相似文献
79.
J. A. Carlisle S. R. Blankenship R. N. Smith A. Chaiken R. P. Michel T. van Buuren L. J. Terminello J. J. Jia T. A. Callcott D. L. Ederer 《Journal of Cluster Science》1999,10(4):591-599
Soft x-ray fluorescence spectroscopy has been used to examine the electronic structure of deeply buried silicide thin films that arise in Fe/Si multilayers. These systems exhibit antiferromagnetic (AF) coupling of the Fe layers, despite their lack of a noble metal spacer layer found in most GMR materials. Also, the degree of coupling is very dependent on preparation conditions, especially spacer layer thickness and growth temperature. The valence band spectra are quite different for films with different spacerlayer thickness yet are very similar for films grown at different growth temperatures. The latter result is surprising since AF coupling is strongly dependent on growth temperature. Combining near-edge x-ray absorption with the fluorescence data demonstrates that the local bonding structure in the silicide spacer layer in epitaxial films which exhibit AF coupling are metallic. These results indicate the equal roles of crystalline coherence and electronic structure in determining the magnetic properties of these systems. 相似文献
80.
Polyelectrolytes offer a widespread potential for the defined modification of planar inorganic or polymer surfaces. Essential parameters for the regular adsorption of subsequent polymer layers by electrostatic interactions are the charge of polyelectrolyte and of the outermost surface region, the surface of the substrate, and the molar mass of the polyelectrolyte. To study such effects in mono- and multilayers we used poly(diallyldimethylammonium chloride (PD) with a molar mass from 5000 to 400000 g/mol as a strong polycation and poly(ethyleneimine) (PEI) with 75000 g/mol as a weak polycation and poly(sodium styrenesulfonate) (PSS) from 70000 to 1Mio g/mol in the diluted and semi-diluted region. The characterization of the layers was performed by streaming potential, in-situ SPR and UV-Vis spectroscopy. Thereby the layer built up at the solid/liquid-interface could be followed and quantified at the molecular level. SPR revealed that the thicknesses of the multilayer depends strongly on pK values of the polyelectrolyte (strong or weak) and the molar masses. We observed a linear growth if both polyelectrolytes are strong and an exponential growth if one polyelectrolyte is weak. The thickness increased with higher molar masses of the polyelectrolytes. The process was followed in-situ in short time steps. 相似文献