Ultrafast heating-induced magnetization switching in ferrimagnets.

We study theoretically the light-induced magnetization switching in a binary ferrimagnet of the type [Formula: see text], randomly occupied by two different species of magnetic ions. The localized spins are coupled with spins of itinerant electrons via s-d exchange interaction. Model parameters are chosen so that to achieve similarity between magnetic characteristics of the model and those of ferrimagnetic rare-earth-transition metal GdFeCo alloys.

Coherence-mediated laser control of exciton and trion spins in CdTe/CdMgTe quantum wells studied by the magneto-optical Kerr effect.

Two temporally non-overlapping linearly cross-polarized 140 fs laser pulses are shown to control the spin polarization in a three-level system. Simultaneous excitation of the two excited states triggers quantum beatings originating from the interference of the wavefunctions corresponding to different spin sublevels of the states. Although the beatings are not seen in the spin densities of the excited states they are clearly observed in the magneto-optical Kerr effect.

Impulsive generation of coherent magnons by linearly polarized light in the easy-plane antiferromagnet FeBO3.

Polarization-dependent excitation of coherent spin precession by 150 fs linearly polarized laser pulses is observed in the easy-plane antiferromagnet FeBO3. We show that the mechanism of excitation is impulsive stimulated Raman scattering. This process is shown to be determined not only by the magneto-optical constants of the material, but also by the properties of the spin precession itself.

Ultrafast optical pumping of spin and orbital polarizations in the antiferromagnetic Mott insulators R(2)CuO(4).

We demonstrate that optical pumping by circularly polarized light at the charge-transfer transition can induce spin and orbital polarizations in the strongly correlated Mott insulators R(2)CuO(4) (R=Pr, Nd, Sm) providing a means of ultrafast nonlinear manipulation of spin states on time scales of less than 150 fs. We propose a model which includes both orbital- and spin-related processes possessing different spectral and temporal properties. This allows us to model the optical response of antiferromagnetic Mott insulators to circularly polarized light and estimate the spin relaxation time as tau(s) approximately 30-50 fs.

[Electrophoretic properties of a population of Escherichia coli cells studied by microelectrophoresis].

The technique of microelectrophoresis was used to measure the rate of E. coli cell motility under the action of a constant electric field, and the electrokinetic potential (xi-potential) was calculated from the experimental data. As was shown by analysing the results for a sample from 100 cells, the property varied within a wide range which exceeded several times the error of a single measurement.

[Studies on the coil-globule transition by the Monte-Carlo method].

The results of a dynamical Monte-Carlo study on the coil-globule and globule-coil transitions are presented. Self-avoiding chains of lengths N = 32 and 64 are investigated. The kinetic model included two- and three-bonds flips.