214 research outputs found
Layer-resolved optical conductivity of Co|Pt multilayers
The complex optical conductivity tensor is calculated for the Co|Pt systems
by applying a contour integration technique within the framework of the
spin-polarized relativistic screened Korringa-Kohn-Rostoker method. It is shown
that the optical conductivity of the Co|Pt multilayer systems is dominated by
contributions arising from the Pt cap and/or substrate layers.Comment: 7 pages (LaTeX), 2 (a,b) figures (Encapsulated PostScript), J. Magn.
Magn. Materials, in pres
Magneto-optical properties of Co|Pt multilayer systems
We are reporting, for the first time in the literature, theoretical Kerr
spectra of Co|Pt multilayer systems as obtained on a first principles basis
including multiple reflections and interferences from all the boundaries
in-between the layers.Comment: 4 pages (LaTeX), 1 (a,b) figures (Encapsulated PostScript), J. Appl.
Physics, in pres
Reorientation phase transitions in thin magnetic films: a review of the classical vector spin model within the mean field approach
The ground state and the finite temperature phase diagrams with respect to
magnetic configurations are studied systematically for thin magnetic films in
terms of a classical Heisenberg model including magnetic dipole-dipole
interaction and uniaxial anisotropy. Simple relations are derived for the
occurrence of the various phase boundaries between the different regions of the
magnetic orientations. In particular, the range of the first and second order
reorientation phase transitions are determined for bi- and trilayers.Comment: 23 pages, LaTeX + 7 figures (Encapsulated PostScript), submitted to
Philosophical Magazine B (Feb. 28, 2001
Formation of magnetic skyrmions with tunable properties in PdFe bilayer deposited on Ir(111)
We perform an extensive study of the spin-configurations in a PdFe bilayer on
Ir(111) in terms of ab initio and spin-model calculations. We use the
spin-cluster expansion technique to obtain spin model parameters, and solve the
Landau-Lifshitz-Gilbert equations at zero temperature. In particular, we focus
on effects of layer relaxations and the evolution of the magnetic ground state
in external magnetic field. In the absence of magnetic field, we find a
spin-spiral ground state, while applying external magnetic field skyrmions are
generated in the system. Based on energy calculations of frozen spin
configurations with varying magnetic field we obtain excellent agreement for
the phase boundaries with available experiments. We find that the wave length
of spin-spirals and the diameter of skyrmions decrease with increasing inward
Fe layer relaxation which is correlated with the increasing ratio of the
nearest-neighbor Dzyaloshinskii-Moriya interaction and the isotropic exchange
coupling, . Our results also indicate that the applied field needed to
stabilize the skyrmion lattice increases when the diameter of individual
skyrmions decreases. Based on our observations, we suggest that the formation
of the skyrmion lattice can be tuned by small structural modification of the
thin film.Comment: 7 pages, 5 figures, 2 table
Role of temperature-dependent spin model parameters in ultra-fast magnetization dynamics
In the spirit of multi-scale modelling magnetization dynamics at elevated
temperature is often simulated in terms of a spin model where the model
parameters are derived from first principles. While these parameters are mostly
assumed temperature-independent and thermal properties arise from spin
fluctuations only, other scenarios are also possible. Choosing bcc Fe as an
example, we investigate the influence of different kinds of model assumptions
on ultra-fast spin dynamics, where following a femtosecond laser pulse a sample
is demagnetized due to a sudden rise of the electron temperature. While
different model assumptions do not affect the simulational results
qualitatively, their details do depend on the nature of the modelling.Comment: 8 pages, 6 figure
Exchange Bias driven by Dzyaloshinskii-Moriya interactions
The exchange bias effect in compensated IrMn3/Co(111) system is studied using
multiscale modeling from "ab initio" to atomistic calculations. We evaluate
numerically the out-of-plane hysteresis loops of the bi-layer for different
thickness of the ferromagnetic layer. The results show the existence of a
perpendicular exchange bias field and an enhancement of the coercivity of the
system. In order to elucidate the possible origin of the exchange bias, we
analyze the hysteresis loops of a selected bi-layer by tuning the different
contributions to the exchange interactions across the interface. Our results
indicate that the exchange bias is primarily induced by the
Dzyaloshinskii-Moriya interactions, while the coercivity is increased mainly
due to a spin-flop mechanism
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