7 research outputs found
Spin wave calculation of the field-dependent magnetization pattern around an impurity in Heisenberg antiferromagnets
We consider the magnetic-field dependent spatial magnetization pattern around
a general impurity embedded in a Heisenberg antiferromagnet using both an
analytical and a numerical spin wave approach. The results are compared to
quantum Monte Carlo simulations. The decay of the magnetization pattern away
from the impurity follows a universal form which reflects the properties of the
pure antiferromagnetic Heisenberg model. Only the overall magnitude of the
induced magnetization depends also on the size of the impurity spin and the
impurity coupling.Comment: 11 pages, 11 figure
Spectral signatures of magnetic Bloch oscillations in one-dimensional easy-axis ferromagnets
Domain walls in a one-dimensional gapped easy-axis ferromagnet can exhibit
Bloch oscillations in an applied magnetic field. We investigate how exchange
couplings modify this behavior within an approximation based on noninteracting
domain-wall bound states. In particular, we obtain analytical results for the
spectrum and the dynamic structure factor, and show where in momentum space to
expect equidistant energy levels, the Wannier-Zeeman ladder, which is the
spectral signature of magnetic Bloch oscillations. We compare our results to
previous calculations employing a single domain-wall approximation, and make
predictions relevant for the material .Comment: 12 pages, 14 figure
Spin light of electron in matter
We further generalize the powerful method, which we have recently developed
for description of the background matter influence on neutrinos, for the case
of an electron moving in matter. On the basis of the modified Dirac equation
for the electron, accounting for the standard model interaction with particles
of the background, we predict and investigate in some detail a new mechanism of
the electromagnetic radiation that is emitted by moving in matter electron due
to its magnetic moment. We have termed this radiation the ``spin light of
electron" in matter and predicted that this radiation can have consequences
accessible for experimental observations in astrophysical and cosmological
settings.Comment: 5 pages in LaTex, in: "Particle Physics at the Year of 250th
Anniversary of Moscow University", ed. by A.Studenikin, World Scientific,
Singapore, 2006, p. 73 (Proceedings of the 12th Lomonosov Conference on
Elementary Particle Physics, August 2005, Moscow
Numerical simulations of laser-excited magnetic Bloch oscillations
We propose to use lasers to excite magnetic Bloch oscillations in one-dimensional easy-axis ferromagnets at low temperatures. This proposal is investigated numerically in detail for material parameters relevant for CoCl2â
2H2O.
© 2013 American Physical Societ
Justification of the Application of Resource-Saving Technology for the Restoration of Metal-Intensive Rear Semi-Axles of Trucks Using Hot Plastic Deformation
The article is devoted to the substantiation of technological foundations for the restoration of extremely worn-out, metal-consuming, and resource-consuming parts, in a method consisting of applying a compensating metal wear with subsequent plastic deformation. Currently, there are no technologies for their restoration in a repair facility that guarantee the resilience of the factory product. The proposed technological process of repair consists of butt welding onto the end of the spline semi-axle shank, compensating for the wear of the metal, the volume of which takes into account the losses resulting from the wear of the slots, as well as allowances for their machining. In the example of forging the axle shaft of a truck’s driving axle, the regularities of the plastic flow of metal during part deformation in the stamp are revealed. In the process of hot volumetric upsetting of long cylindrical parts with a variable diameter, it is important to know the possible directions of metal movements, as well as the energy-power characteristics of the process at various stages of forging. The evaluation criteria of the level of perfection of the technology were indicators of resource conservation and efficiency of the recovery route. The technological direction of the conducted research was analyzed, step by step, from the standpoint of saving repair materials and energy resources. The results of theoretical studies are crucial in the design of die tooling, for the manufacture of blanks, when restoring the rear axle shafts of trucks with pressure. Production tests carried out on the models, obtained as a result of mathematical processing of experimental data, confirmed the reliability of the experimental information. The introduction of the proposed set of repair equipment for the restoration of semi-axles will allow the formation of additional production in the region for the recycling of worn-out metal-intensive steel parts of agricultural machinery