Study on the Interfacial Characterization of the Co5/Cu3/Co5 trilayer and Co3/Cu/Co/Cu3/Co/Cu/Co3 Multilayer

2004 ◽  
Vol 19 (3) ◽  
pp. 741-745 ◽  
Author(s):  
Xiaoyu Yuan ◽  
Xiaofang Bi ◽  
Jiaxiang Shang ◽  
Huibin Xu
Keyword(s):  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Zero Field ◽  
Local Spin Density Approximation ◽  
Discrete Variational Method ◽  
Ferromagnetic Layers ◽  
Calculation Results ◽  
Spin Dependent Scattering ◽  
The Moment

Comprehensive results are presented on the influence of interfaces on electronic structure and giant magnetoresistance (GMR). Two structures were calculated for Co5/Cu3/Co5 and Co3/Cu/Co/Cu3/Co/Cu/Co3, where numbers stand for monolayer numbers of atoms, by employing the discrete variational method in the framework of the local spin density approximation. It has been found that the electron spin-dependent scattering is very strong at the interfaces compared to the interiors of the ferromagnetic layers, independent of the moment alignment configuration. The calculation results of total energy for various magnetization configuration revealed that antiferromagnetic exchange coupling was present between any of the ferromagnetic layers separated by Cu layers at zero field in the Co3/Cu/Co/Cu3/Co/Cu/Co3. The evaluated GMR ratio for the Co3/Cu/Co/Cu3/Co/Cu/Co3 (about 35.1%) was much larger than that of the Co5/Cu3/Co5 (about 21.0%), indicating large GMR effect could be expected with more interfaces when the thicknesses were the same. The result also indicated that the negative polarization of 4s electrons could reduce the GMR effect.

Giant Magnetoresistance Induced by Ultrathin Magnetic Layers

1997 ◽  
Vol 475 ◽  
Author(s):  
G.J. Strijkers ◽  
H.J.M. Swagten ◽  
A.H.M. Mettler ◽  
M.M.H. Willekens ◽  
W.J.M. De Jonge
Keyword(s):  
Giant Magnetoresistance ◽  
Spin Valve ◽  
Short Length ◽  
Spin Valves ◽  
Length Scale ◽  
Magnetic Layers ◽  
Ferromagnetic Layers ◽  
Experimental Tool ◽  
Spin Dependent Scattering

ABSTRACTWe introduce an interface selective structure, composed of a spin-valve on top of which a thick nonmagnetic back layer is deposited as a straightforward experimental tool to measure the GMR induced by ultrathin magnetic layers. The interface selectivity of spin-dependent scattering is evidenced by calculations and illustrated in both Co/Cu/Co and Ni80Fe20/Cu/Ni80Fe20 spin-valves by an almost discontinuous behavior in the GMR ratio. The temperture dependence of the extremely short length scale associated with this discontinuity is discussed in relation to the structure of ultrathin ferromagnetic layers.

Temperature Dependence of the Magnetoresistance of Co/Re Superlattices

2001 ◽  
Vol 674 ◽  
Author(s):  
Timothy Charlton ◽  
David Lederman ◽  
Gian P. Felcher
Keyword(s):  
Temperature Dependence ◽  
Giant Magnetoresistance ◽  
Easy Axis ◽  
Superconducting Magnet ◽  
Film Plane ◽  
Temperature Dependent ◽  
Ferromagnetic Layers ◽  
Magnetic Easy Axis ◽  
Spin Dependent Scattering ◽  
The Magnetic Field

ABSTRACTHcp (10.0) Co/Re superlattices were grown by dc magnetron sputtering on sapphire (11.0) substrates with the [00.1] direction of the superlattice in the film plane. The temperature-dependent magnetoresistance (MR) was measured on samples patterned by photolithography from 10 K to 300 K in a 5.5 T superconducting magnet. The pattern allows the measurement of the MR with the current (I) and the magnetic field (H) parallel or perpendicular to the magnetic easy axis (c, the [00.1] direction). Measurements at 5 K on an antiferromagnetically-coupled sample shows dips in the MR near H = 0 when H ∕∕ c and H ⊥ I, dips below the saturation value at H ∼ 2.5 kOe for H ∕∕ c and H ∕∕ I configuration due to the competition between the anisotropic magnetoresistance (AMR) and the giant magnetoresistance (GMR). Since the AMR is dependent on the transport within the ferromagnetic layers, the temperature dependence yields information about the relative magnitudes of interface vs. bulk spin-dependent scattering. Our analysis shows that the GMR is anisotropic and that the spin-dependent scattering occurs predominantly at the interfaces only for certain configurations.

SEMPA Studies of Exchange Coupling in Magnetic Multilayers

MRS Bulletin ◽  
1995 ◽  
Vol 20 (10) ◽  
pp. 30-33 ◽  
Author(s):  
R.J. Celotta ◽  
D.T. Pierce ◽  
J. Unguris
Keyword(s):  
Magnetic Field ◽  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Large Change ◽  
Magnetic Multilayers ◽  
Information Storage ◽  
Conduction Electrons ◽  
Spacer Layer ◽  
Ferromagnetic Layers ◽  
Oscillatory Coupling

In the late 1980s, a number of exciting yet puzzling observations resulted from experiments investigating the coupling between two ferromagnetic layers separated by a nonferromagnetic spacer layer. A pioneering experiment by Grünberg et al. showed that Fe layers separated by a thin Cr spacer aligned with antiparallel magnetization, but with Au as the spacer layer, a parallel alignment occurred. The long-range magnetic dipole from each layer would tend to explain antiparallel alignment; small pinholes in the spacer layer would produce parallel alignment. Alternatively, the layers might be coupled through the spacer-layer conduction electrons by the Ruder man-Kittel-Kasuya-Yosida (RKKY) effect. This was expected to produce an oscillation in coupling as the spacer thickness increased, that is, an oscillation between parallel and antiparallel alignment. Oscillatory coupling was first observed by Parkin et al. Researchers had also found that, at spacer thicknesses where antiparallel alignment occurred, the Fe/Cr/Fe system can exhibit a giant magnetoresistance (GMR) effect, that is, an anomalously large change in resistance when a magnetic field is applied. The potential technological importance of the GMR effect to magnetic sensing and magnetic information storage added further impetus to the already rapidly growing area of research in magnetic multilayers.

ChemInform Abstract: Layered Magnetic Structures: Interlayer Exchange Coupling and Giant magnetoresistance

ChemInform ◽  
2010 ◽  
Vol 26 (32) ◽  
pp. no-no
Author(s):  
A. FERT ◽  
P. GRUENBERG ◽  
A. BARTHELEMY ◽  
F. PETROFF ◽  
W. ZINN
Keyword(s):  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Interlayer Exchange Coupling ◽  
Magnetic Structures ◽  
Interlayer Exchange

La structure de classes québécoise au 19e siècle et le problème de l'articulation des modes de production

1981 ◽  
Vol 14 (3) ◽  
pp. 487-518
Author(s):  
Gérald Bernier
Keyword(s):  
Census Data ◽  
New France ◽  
Class Structure ◽  
Capitalist Development ◽  
Single Class ◽  
The Moment ◽  
Empirical Demonstration ◽  
Work Done ◽  
The Impact

The study of social classes in the nineteenth century requires the development of conceptual tools able to explain the impact of the Conquest on the pre-existant social structures in determining transformations of the class structure during the subsequent decades.This article examines the work done on this question by Marxist writers. The author criticizes certain conclusions which have been drawn and which suggest deficiencies at a theoretical level. The objections relate to the marked tendency of these conclusions to perceive the structural effects of the Conquest in terms of the formation of a double-class structure characterized by “ethnic origins.” Specifically, the author challenges the notion of the division itself, as well as the criterion on which the division is based.The author proposes that an analysis centred upon the concepts relating to a problem of the transition and linkage of different modes of production permits a more satisfying interpretation, if accompanied by a certain number of considerations of the “upside” and “downside” of the Conquest. To this end, the argument is based on a characterization of New France in terms of the domination of the relations of production of the feudal type and on an analysis of metropolitan centres with intent to evaluate their level of capitalist development at the moment of their respective colonial penetration in Canada. The results of this approach permit one to posit the existence of a single-class structure, characterized principally by the existence of elements connecting diverse modes and forms of production, whose origin reflects the unequal state of economic development in the two metropolitan centres.The empirical demonstration rests on the census data of 1851–1852 and on the complementary information drawn from the works of historians.

scholarly journals One-relator groups and algebras related to polyhedral products

2021 ◽  
pp. 1-20
Author(s):  
Jelena Grbić ◽  
George Simmons ◽  
Marina Ilyasova ◽  
Taras Panov
Keyword(s):  
Homology Group ◽  
Homotopy Theory ◽  
Commutator Subgroup ◽  
Homology Groups ◽  
Homological Characterization ◽  
One Relator Groups ◽  
Combinatorial Condition ◽  
The Moment ◽  
Necessary And Sufficient

We link distinct concepts of geometric group theory and homotopy theory through underlying combinatorics. For a flag simplicial complex $K$ , we specify a necessary and sufficient combinatorial condition for the commutator subgroup $RC_K'$ of a right-angled Coxeter group, viewed as the fundamental group of the real moment-angle complex $\mathcal {R}_K$ , to be a one-relator group; and for the Pontryagin algebra $H_{*}(\Omega \mathcal {Z}_K)$ of the moment-angle complex to be a one-relator algebra. We also give a homological characterization of these properties. For $RC_K'$ , it is given by a condition on the homology group $H_2(\mathcal {R}_K)$ , whereas for $H_{*}(\Omega \mathcal {Z}_K)$ it is stated in terms of the bigrading of the homology groups of $\mathcal {Z}_K$ .

Calculating Mechanics Characteristics of Single-Walled Carbon Nanotube Materials by Finite Element Method

2017 ◽  
Vol 730 ◽  
pp. 548-553
Author(s):  
Jing Ge ◽  
Hao Jiang ◽  
Zhen Yu Sun ◽  
Guo Jun Yu ◽  
Bo Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Radial Direction ◽  
Element Model ◽  
Beam Element ◽  
Beam Position ◽  
Single Walled Carbon ◽  
Finite Element Software ◽  
Calculation Results ◽  
The Moment

In this paper, we establish the mechanical property analysis of Single-walled Carbon Nanotubes (SWCNTs) modified beam element model based on the molecular structural mechanics method. Then we study the mechanical properties of their radial direction characteristics using the finite element software Abaqus. The model simulated the different bending stiffness with rectangular section beam elements C-C chemical force field. When the graphene curled into arbitrary chirality of SWCNTs spatial structure, the adjacent beam position will change the moment of inertia of the section of the beam. Compared with the original beam element model and the calculation results, we found that the established model largely reduced the overestimate of the original model of mechanical properties on the radial direction of the SWCNTs. At the same time, compared with other methods available in the literature results and the experimental data, the results can be in good agreement.

scholarly journals Interlayer exchange coupling and giant magnetoresistance inFe/V(001) superlattices

2002 ◽  
Vol 65 (21) ◽  
Author(s):  
A. Broddefalk ◽  
R. Mathieu ◽  
P. Nordblad ◽  
P. Blomqvist ◽  
R. Wäppling ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Interlayer Exchange Coupling ◽  
Interlayer Exchange

scholarly journals Preliminary Characterization of Wild Grapevine Populations (Vitis vinifera ssp. sylvestris) Grown Along the Danube River

2013 ◽  
Vol 41 (2) ◽  
pp. 472 ◽  
Author(s):  
Carmen F. POPESCU ◽  
Liviu C. DEJEU ◽  
Rafael R. OCETE
Keyword(s):  
Vitis Vinifera ◽  
Morphological Analysis ◽  
Danube River ◽  
Vitis Vinifera L ◽  
Meristematic Tissue ◽  
The Danube River ◽  
Wild Grapevine ◽  
The Moment

The individuals belonging to three different groups of wild grapevines populations Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi harvested along, or near the Danube River, were described by means of usual ampelographic methods. The twenty standardized descriptors used for morphological analysis revealed obvious differentiation among analyzed populations. Out of 65 individuals, a half produced flowers with separate sex and a high proportion of them were males (70%). Pollen measurements on light microscope provided information on differences in pollen size among inside wild grapevine populations of V. sylvestris with the polar length varying between 15.3 and 23 μm and the equatorial length between 15.5 and 24.4μm. The in vitro regenerative potential from meristematic tissue tested with each phenotype showed that the moment of differentiation, the aspect of proliferative structures and the rate of multiplication varied inside these wild grapevine populations, without any correlation with the location of harvesting. Our results provided valuable information about these Vitis vinifera ssp. sylvestris populations, possible to be used as starting plant material for research in general and further breeding of cultivars and grapevine rootstocks.

The Scope of the Conceptual

2012 ◽  
Author(s):  
Stephen Laurence ◽  
Eric Margolis
Keyword(s):  
Natural Language ◽  
Social Practice ◽  
Donald Davidson ◽  
Human Beings ◽  
Conceptual Content ◽  
Michael Dummett ◽  
Contemporary Philosopher ◽  
Conceptual Thought ◽  
The Moment

This article explains different views on concepts, which are among the most fundamental constructs in cognitive science. Michael Dummett argues that nonhuman animals are not capable of full-fledged conceptual thought but only a diminished form of thought, which he calls, proto-thought. Human beings can remove themselves from the moment and can rise above the confined world of current perceptions because of their linguistic abilities. Donald Davidson, a contemporary philosopher, denies that animals are capable of conceptual thought and claim that conceptual content requires a rich inferential network. Donald Davidson made an argument against animals having conceptual thought. Davidson's original formulation of the argument begins with the claim that having a belief requires having the concept of a belief but adds that having the concept of belief requires possession of a natural language. It follows, then, that to have a belief requires facility with natural language. The characterization of the conceptual/nonconceptual distinction that is implicit in Davidson's metacognitive argument is a complex one involving a capacity for belief about beliefs, a concept of belief, and concepts of truth and falsity. Both Robert Brandom and John McDowell argued that conceptual thought requires more than a capacity for detection. They claim that conceptual thought requires the ability to appreciate the reasons that would justify a given concept's application and use, and this, in turn, is inherently a social practice that is dependent on natural language

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