4,154 research outputs found
Exchange shift of stripe domains in antiferromagnetically coupled multilayers
Antiferromagnetically coupled multilayers with perpendicular anisotropy, as
[CoPt]/Ru, Co/Ir, Fe/Au, display ferromagnetic stripe phases as the ground
states. It is theoretically shown that the antiferromagnetic interlayer
exchange causes a relative shift of domains in adjacent layers. This ``exchange
shift'' is responsible for several recently observed effects: an anomalous
broadening of domain walls, the formation of so-called ``tiger-tail'' patterns,
and a ``mixed state'' of antiferromagnetic and ferromagnetic domains in
[CoPt]/Ru multilayers. The derived analitical relations between the values of
the shift and the strength of antiferromagnetic coupling provide an effective
method for a quantitative determination of the interlayer exchange
interactions.Comment: 4 pages, 3 figure
Theory of vortex states in magnetic nanodisks with induced Dzyaloshinskii-Moriya interactions
Vortex states in magnetic nanodisks are essentially affected by
surface/interface induced Dzyaloshinskii-Moriya interactions. Within a
micromagnetic approach we calculate the equilibrium sizes and shape of the
vortices as functions of magnetic field, the material and geometrical
parameters of nanodisks. It was found that the Dzyaloshinskii-Moriya coupling
can considerably increase sizes of vortices with "right" chirality and suppress
vortices with opposite chirality. This allows to form a bistable system of
homochiral vortices as a basic element for storage applications.Comment: 8 pages, 8 figure
Skyrmionic textures in chiral magnets
In non-centrosymmetric magnets the chiral Dzyaloshinskii-Moriya exchange
stabilizes Skyrmion-strings as excitations which may condense into multiply
modulated phases. Such extended Skyrmionic textures are determined by the
stability of the localized "solitonic" Skyrmion cores and their geometrical
incompatibility which frustrates regular space-filling. We present numerically
exact solutions for Skyrmion lattices and formulate basic properties of the
Skyrmionic states.Comment: Conference information: The International Conference on Magnetism
(ICM), Karlsruhe, July 26 - 31, 200
Low-temperature kinetics of exciton-exciton annihilation of weakly localized one-dimensional Frenkel excitons
We present results of numerical simulations of the kinetics of
exciton-exciton annihilation of weakly localized one-dimensional Frenkel
excitons at low temperatures. We find that the kinetics is represented by two
well-distinguished components: a fast short-time decay and a very slow
long-time tail. The former arises from excitons that initially reside in states
belonging to the same localization segment of the chain, while the slow
component is caused by excitons created on different localization segments. We
show that the usual bi-molecular theory fails in the description of the
behavior found. We also present a qualitative analytical explanation of the
non-exponential behavior observed in both the short- and the long-time decay
components.Comment: Published in J. Chem. Phys. 114, 1 April (2001
Multilevel Clustering Fault Model for IC Manufacture
A hierarchical approach to the construction of compound distributions for
process-induced faults in IC manufacture is proposed. Within this framework,
the negative binomial distribution is treated as level-1 models. The
hierarchical approach to fault distribution offers an integrated picture of how
fault density varies from region to region within a wafer, from wafer to wafer
within a batch, and so on. A theory of compound-distribution hierarchies is
developed by means of generating functions. A study of correlations, which
naturally appears in microelectronics due to the batch character of IC
manufacture, is proposed. Taking these correlations into account is of
significant importance for developing procedures for statistical quality
control in IC manufacture. With respect to applications, hierarchies of yield
means and yield probability-density functions are considered.Comment: 10 pages, the International Conference "Micro- and Nanoelectronics-
2003" (ICMNE-2003),Zvenigorod, Moscow district, Russia, October 6-10, 200
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