Energy features of bound polaron states in colored NaCl and KBr crystals

Thermoionization of bound polaron states in γ-irradiated KBr and NaCl crystals is studied in the temperature range 71–104 K. It is shown that the complex shape of the thermoionization curves in this temperature range is determined by the presence of three types of electron traps that are unstable (each trap decays according to an exponential law) and one type of stable trap. This explains a sharp break on the dependence of the logarithm of the lifetime on the reciprocal temperature, which is observed for a KBr crystal, as well as a number of discrepancies in the results obtained by other authors. The physical parameters (activation energy H for thermoionization, the optical absorption peak E _op, the spectral photoionization threshold E _i, and the energies of phonons participating in the optical absorption, L _op, and in photoionization, L _phc) obtained in the present paper and in our earlier studies on KCl, NaCl, and KBr crystals are analyzed, and the relations between these quantities predicted by available theories are considered.     

Domain Structure and Magnetization Reversal Micromechanisms in Quasi-Two-Dimensional Exchange-Biased Nanomagnetics

Physics of the Solid State - Abstract—The domain structure and magnetization reversal mechanisms are studied in quasi-two-dimensional exchange-biased NiFe/FeMn and NiFe/NiO nanomagnetics,...     

Universality and scaling of unstable plastic flow

The statistics of the jumplike plastic deformation of a Cu–Be alloy under the conditions of a low-temperature unstable plastic flow is studied experimentally. At a high strain rate, the parameters of the load jumps are found to be related by power laws, which corresponds to a scale-invariant behavior. A comparison with the data obtained for another mechanism of plastic instability, namely, the Portevin–Le Chatelier effect, points to the existence of universal laws governing the dynamics of a dislocation ensemble in the conditions of plastic instability.     

Infuence of plastic deformation on IR photoconduction stimulated by <Emphasis Type="Italic">F</Emphasis>-center-exciting light in colored NaCl crystals

Plastic deformation of NaCl crystals colored by irradiation with gamma rays was found to lead to the occurrence of a band in the spectrum of IR photoconductivity stimulated by F-center-exciting light. This band corresponds to photon energies lying in the range from 0.65 to 1.11 eV and higher and has two distinct peaks, at 0.74 and 0.88 eV. The position of the former peak correlates well with the spectrum of IR quenching of the photoplastic effect, which suggests that this peak is associated with a dislocation electronic level.