254 research outputs found
Extraordinary magnetooptical effects and transmission through the metal-dielectric plasmonic systems
We report on significant enhancement of the magnetooptical effects in
gyrotropic systems of a metallic film perforated by subwavelength hole arrays
and a uniform dielectric film magnetized perpendicular to its plane.
Calculations, based on a rigorous coupled-wave analysis, demonstrate the
Faraday and Kerr effect spectra having several resonance peaks in the near
infrared range, some of them coinciding with transmittance peaks. Qualitative
analysis revealed that magnetic polaritons being coupled magnetic-film
waveguiding modes with surface plasmons play a crucial role in the observed
effect.Comment: 10 pages, 3 figure
On surface plasmon polariton wavepacket dynamics in metal-dielectric heterostructures
The WKB equations for dynamics of the surface plasmon polariton (SPP)
wavepacket are studied. The dispersion law for the SPP in the metal-dielectric
heterostructure with varying thickness of a perforated dielectric layer is
rigorously calculated and investigated using the scattering matrix method. Two
channels of the SPP wavepacket optical losses related to the absorption in a
metal and to the SPP leakage are analyzed. It is shown that change of the
dielectric layer thickness acts on the SPP as an external force leading to
evolution of its quasimomentum and to the wavepacket reversal or even to the
optical Bloch oscillations (BO). Properties of these phenomena are investigated
and discussed. Typical values of the BO amplitude are about tens of microns and
the period is around tens or hundreds of femtoseconds.Comment: 12 pages, 5 figure
Thermally assisted domain walls quantum tunneling at the high temperature range
A theoretical and numerical investigations of the quantum tunneling of the
domain walls in ferromagnets and weak ferromagnets was performed taking into
account the interaction between walls and thermal excitations of a crystal. The
numerical method for calculations of the probability of a thermally stimulated
quantum depinning as the function of temperature at the wide temperature range
has been evolved.Comment: 5 pages, 3 figure
Inverse Transverse Magneto-Optical Kerr Effect
It is demonstrated that a static in-plane magnetic field is generated in a
ferromagnetic film by p-polarised light obliquely incident on the film. This
phenomenon can be called inverse transverse magneto-optical Kerr effect. The
femtosecond laser pulse of peak intensity of 500 W/{\mu}m2 generates in nickel
an effective magnetic field of about 100 Oe. The value of the effective
magnetic field can be increased by more than an order of magnitude at the
surface plasmon polariton resonance excited in smooth metal dielectric
structures or in plasmonic crystals.Comment: 4 pages, 3 figure
Polarization switching and nonreciprocity in symmetric and asymmetric magnetophotonic multilayers with nonlinear defect
A one-dimensional magnetophotonic crystal with a nonlinear defect placed
either symmetrically or asymmetrically inside the structure is considered.
Simultaneous effects of time-reversal nonreciprocity and nonlinear spatial
asymmetry in the structure are studied. Bistable response is demonstrated in a
such system, accompanied by abrupt polarization switching between two circular
or elliptical polarizations for transmitted and reflected waves. The effect is
explained in terms of field localization at defect-mode spectral resonances and
can be used in the design of thin-film optical isolators and polarization
transformation devices.Comment: 20 pages, 8 figure
Modification of the surface of parts
The increasing wear resistance of parts is one of the main tasks of engineering. The achievement of stable parameters is a difficult task. It depends on capabilities of equipment, type of evaporator, interaction evaporator with the evaporating substance and deposition process.The control system must foresee and identify emerging cracks or damage of the system components. At every stage software of control process system must automatically make the optimal decisions based on information about the process. It also improves the efficiency of the operator. This article focuses on the results of using intelligent control system technological process
Magnetoelectric Effect and Spontaneous Polarization in HoFe(BO) and HoNdFe(BO)
The thermodynamic, magnetic, dielectric, and magnetoelectric properties of
HoFe(BO) and HoNdFe(BO) are
investigated. Both compounds show a second order Ne\'{e}l transition above 30 K
and a first order spin reorientation transition below 10 K.
HoFe(BO) develops a spontaneous electrical polarization below the
Ne\'{e}l temperature (T) which is diminished in external magnetic fields.
No magnetoelectric effect could be observed in HoFe(BO). In
contrast, the solid solution HoNdFe(BO) exhibits
both, a spontaneous polarization below T and a magnetoelectric effect at
higher fields that extends to high temperatures. The superposition of
spontaneous polarization, induced by the internal magnetic field in the ordered
state, and the magnetoelectric polarizations due to the external field results
in a complex behavior of the total polarization measured as a function of
temperature and field.Comment: 12 pages, 15 figure
Spectral dependence of photoinduced spin precession in DyFeO3
Spin precession was nonthermally induced by an ultrashort laser pulse in
orthoferrite DyFeO3 with a pump-probe technique. Both circularly and linearly
polarized pulses led to spin precessions; these phenomena are interpreted as
the inverse Faraday effect and the inverse Cotton-Mouton effect, respectively.
For both cases, the same mode of spin precession was excited; the precession
frequencies and polarization were the same, but the phases of oscillations were
different. We have shown theoretically and experimentally that the analysis of
phases can distinguish between these two mechanisms. We have demonstrated
experimentally that in the visible region, the inverse Faraday effect was
dominant, whereas the inverse Cotton-Mouton effect became relatively prominent
in the near-infrared region.Comment: 27 pages, 8 figure
Terahertz spectroscopy of electromagnons in Eu_{1-x}Y_xMnO_3
Dielectric permittivity spectra of yttrium-doped EuMnO in the composition
range 0 =< x =< 0.5 have been investigated in the terahertz frequency range.
Magnetoelectric contributions to the permittivity were observed in all
compositions for ac electric fields parallel to the crystallographic a-axis.
Well defined electromagnons exist for x >= 0.2 close to \nu ~ 20 cm^{-1} and
with dielectric strength strongly increasing on doping. In addition to
electromagnons, a broad contribution of magnetoelectric origin is observed for
all compositions. For Eu_{0.8}Y_{0.2}MnO_3 the electromagnons can be suppressed
by external magnetic fields which induce a canted antiferromagnetic phase.
Magnetoelectric effects in the different doping regimes are discussed in
detail.Comment: 7 pages, 9 figures include
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