摘要:

AbstractThe magnetostriction of some amorphous alloys is investigated in the temperature range of the magnetic phase transition. Measurements are made with the help of a method described previously, and which is based on the observation of the macroscopical torsional strain under a longitudinal electrical current. The magnetostriction near the ferromagnetic phase transition is found to obey a (Tc–T)χ‐law with critical exponents depending on the type of alloy and values varying in the range of χ = 1.1 t

ISSN:0370-1972    

DOI:10.1002/pssb.2221330119

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe band structure in the high‐symmetry points of the TIGaSe2, Brillouin zone is calculated by the pseudopotential method. The top of the valence band is found to be located at the Γ point. The bottom of the conduction band is located at the line Γ–Y and the additional extremum of this band – at the point Γ of the Brillouin zone of TlGaSe2. The data obtained are compared with the results of previous band calculations and optical absorption data of

ISSN:0370-1972    

DOI:10.1002/pssb.2221330120

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractSelection rules for intervalley transitions in TlSe structural crystals are obtained. The results are presented both, without and with regard to the electron spin.

ISSN:0370-1972    

DOI:10.1002/pssb.2221330121

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCorrected formulae for the total energy distribution, the emission current density, and the inversion temperature are derived under the condition that the field‐electron emission takes place from a free‐electron metal. The corrections relate to the series truncation approximating the WKB phase integral inherent in the analytic approximation of the electron tunneling probability. The assumed approximation for the phase integral takes into account not only the zero and first order terms, present in the existing theory, but also the quadratic term. The expression for the total energy distribution, obtained on this basis, is in typical circumstances valid for field emission in the electron energy range of |ε| ≦ 1.5 eV with respect to the Fermi energy. The accuracy of the approximations used is also dis

ISSN:0370-1972    

DOI:10.1002/pssb.2221330122

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractTwo schemes of the crystalline potential for the slow electron in the conduction band of alkalihalides are proposed. The first one (semiempirical) is based on the assumption that in the case of an ion in the crystal one can use the same energy dependence of logarithmic derivatives (of radial solutions at the atomic sphere radius) as in the case of the isolated ion. The modifications required consist in some potential corrections, that are due to the Madelung field as well as to the relaxation and polarization response for both, hole and electron. The second model (ab initio) suggests the straightforward solution of Poisson's equation. Both approaches are compared, so it is found that they lead to satisfactory agreement for a wide energy interval in the continuum.

ISSN:0370-1972    

DOI:10.1002/pssb.2221330123

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAn energy straggling distribution is incorporated in the Monte‐Carlo simulation of keV‐electron scattering in solids. This distribution is obtained by modifying the original Blunck and Leisegang distribution based on the Landau theory. The average energy loss of the distribution is adjusted to fit the stopping power of the Rao Sahib and Wittry equation (the modified Bethe equation). Since an electron trajectory is simulated by a stepwise fashion, the energy straggling of an electron even in a bulk specimen can be calculated. By comparing with an experimental energy distribution of transmitted electrons from a thin film, the validity of the present model is discussed. The electron path length distribution in a bulk specimen due to the energy straggling is also discus

ISSN:0370-1972    

DOI:10.1002/pssb.2221330124

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe nondipole radiation of electrons is considered for any shape of the interplane potential. A concrete analysis and comparison with the radiation of positrons are carried out for a potential of the „inverse parabola”︁ type. It is shown that for the description of the radiation of particles with energyeε ⪅ 10 GeV in the region of the maximum of the spectral distribution it is possible to take into account the few first harmonics of the motion only. This substantially simplifies the calculation, especially for the potentials with complex shape. The diagrams which illustrate the radiation spectrum as a function of the angular width and of the direction of beam incidence in a thin crystal, are depicted. A detailed comparison of the results with available experimental data

ISSN:0370-1972    

DOI:10.1002/pssb.2221330125

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe plasmon bands are observed in the X‐ray spectra of polycrystalline Be, using CuKα1, SaL2radiation fork>kc. The spectra show four peaks at the long wavelength region of Raman bands, assigned to the 3spxpy‐3spzsplitting of the 3ps hybridized

ISSN:0370-1972    

DOI:10.1002/pssb.2221330126

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of the screening of the electron‐phonon interaction on the polaron binding energy (E) and the polaron mass (m*) is investigated within second order perturbation theory and for different approximations to the two‐dimensional electron gas response (random‐phase approximation, Hartree‐Fock and Thomas‐Fermi approximation). For the electron–phonon contribution to the polaron ground state energy a dynamical screening is applied which takes into account the dielectric response at all frequencies. The influence of the finite width of the electron layer onEandm*is investigated. The results are applied to GaAsAlxGa1–xAs heterostructures and it is found that the mass renormalization forne= 1011cm−2is 0.4% which is a factor of eight smaller than the effective mass of the unscreened

ISSN:0370-1972    

DOI:10.1002/pssb.2221330127

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractBand structure calculations are carried out for hypothetical nonmagnetic alloys Co2Ga and Co2MnGa and for the ferromagnetic alloy Co2MnGa, all with the L21structure. The results are used to investigate the electrical conductivity of (Co, Ga) and Co(Ga, TM) alloys (where TM is a transition metal), particularly as this involves hopping conduction. Explanation of the latter by the presence of antistructure Co or TM atoms on the Ga subslattice seems to be confirmed although they do not affect normal conduction appreciably. Mn assists hopping conduction less than antistructure Co since it provides fewer good hopping states, albeit better ones.

ISSN:0370-1972    

DOI:10.1002/pssb.2221330128

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY