摘要:

An RBS/ion implanter facility for high-energy ion-surface interaction studies was constructed. The potential application of the facility was demonstrated by studying ion-stimulated processes in Ni films on an Al substrate at elevated temperatures and preferential sputtering of Ni4Mo single crystals. An unusual temperature behaviour for the radiation enhanced diffusion rate in the vicinity of the Curie point for Ni was seen. The sputtering of (001) and (111) faces of Ni4Mo single crystal with 20–80 keV inert gas ions was shown to enrich the surface in Mo, which is the same for both faces.

ISSN:1042-0150    

DOI:10.1080/10420159608211522

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Structure stability of Fe-Cr-Ni alloy for sensitive elastic elements after thermal processing and 4 MeV electron irradiation is investigated by electron transmission microscopy and internal friction methods. It is shown that electron irradiation affects structure and phase composition and leads to temperature stabilization of Young modulus of the alloy.

ISSN:1042-0150    

DOI:10.1080/10420159608211523

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The influence of γ-irradiation on the optical and electrical properties of amorphous InSe thin films was investigated. Optical absorption coefficient (α) of amorphous InSe thin films was represented as a function of photon energy (hμ) and the data were used to deduce the value of the optical energy gap (Egopt), the refractive index (n) and the valence band density of states (gi) of the films. The analysis of the absorption coefficient data revealed the existence of indirect transition with optical energy gap Egopt= 0.98 eV for as-deposited (unirradiated) amorphous InSe films, which increases to 1.15 eV with increasing the γ-doses to 2.5 Mrad.

ISSN:1042-0150    

DOI:10.1080/10420159608211524

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The formation of stationary amorphous layers during high-temperature ion irradiation of semiconductors is considered in the case of 5 keV Ar+ion bombardment of germanium. The dependence of their thickness on substrate temperature and ion flux is studied. It is shown that the thickness of the amorphous layer does not depend on the initial structural state of a sample. Local critical temperatures for ion-beam induced crystallization and amorphization are introduced and their dependence on depth for the given conditions of ion bombardment is obtained. These two parameters are shown to coincide. A model of defect steady-state formation during ion irradiation is proposed.

ISSN:1042-0150    

DOI:10.1080/10420159608211525

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The samples of Al-11.8 at % Zn alloy were irradiated with 2 Mev electrons at a flux of 104electrons/cm2-s for different periods of time. The small angle neutron scattering (SANS) experiments were performed on unirradiated and irradiated samples under identical conditions. The results were obtained in the form of differential scattering cross section, versus momentum transfer vector Q(A0−1). In general, results indicate an initial large drop in the magnitude of peak scattering cross section, increase in the precipitate size and reduction in the number density of the precipitates. More significant changes in these parameters have been noticed as the dose is increased. However, no such changes have been observed in the repeated measurements of post irradiated room temperature aged samples. We thus conclude that the changes induced by irradiation are found to be stable, and the small angle neutron scattering results are reproducible. It is thus concluded that there is an absence of growth in post irradiated room temperature aged Al-Zn alloy.

ISSN:1042-0150    

DOI:10.1080/10420159608211526

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Modified Bridgman method was used to grow Bi2Te3single crystals doped with thallium in the concentration range of 1017−1018atoms/cm3. Experimental values of the electrical conductivity and Hall constant indicate that the introduction of Tl atoms into the lattice of p-Bi2Te3leads to a pronounced suppression of the concentration of holes. Also it follows from the decrease of the absorption coefficient in the IR region that the concentration of holes decreases with increasing content of Tl atoms built into the lattice. Analysis of possible point defects and comparison of the structure of Bi2Te3and TlBiTe2suggest a probable explanation that the mentioned effect could be due to the substitution of the (Te–Bi–Te–Tl–V**Te) + 2e′ fragment for the Te1–Bi–Te2–Bi–Te1five-layer stack in the Bi2Te3structure.

ISSN:1042-0150    

DOI:10.1080/10420159608211527

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The zero-field splittings b20of the tetragonal Gd3+–VMand Gd3+–Li+centers for Gd3+ions in fluoroperovskite crystals have been studied on the basis of the superposition model in which the value of t2ƀ2is obtained from the stress-dependence of EPR spectra for RbCaF3:Gd3+crystal. From the studies, the local structures of both tetragonal centers in fluoroperovskite crystals are obtained and the results are discussed.

ISSN:1042-0150    

DOI:10.1080/10420159608211528

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Photodecomposition of pure and doped KI powder (KI:KOH; KI:KCN; Impurity concentration, 100, 300, 500, 700 and 1000 ppm) to produce free I2molecules during gamma irradiation is studied with the help of absorption ad IR measurements. Large number of I2molecules are formed in pure KI as compared to the doped samples. Hydroxide impurity increases the rate of liberation of I2molecules whereas the cyanide impurity decreases the rate of liberation of I2molecules.

ISSN:1042-0150    

DOI:10.1080/10420159608211529

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The precipitation processes of Eu2+ions in NaBr1−xClxmixed crystals have been studied by fluorescence and Electron Paramagnetic Resonance techniques. The obtained results point out that the Cl-impurity ions are located near to the europium cation vacancy complexes and that these defects can act as nucleation centers producing mixed europium dihalide phases.

ISSN:1042-0150    

DOI:10.1080/10420159608211530

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The frequency (102– 105Hz) dependence of the dielectric properties of lithium rubidium sulphate (LRS) are reported in the vicinity of the transition temperature Tc= 477 K. The a.c. conductivity σ(ω) shows a strong temperature dependence and weak frequency response. The dielectric constant in this region shows a strong frequency dispersion. A Cole-Cole diagram was used to determine the distribution parameter and the molecular relaxation time. The effect of doping with Dy+3, Sm+3and V+3, was also studied. It was found that doping gives rise to localized states which produce a disorder in the structure of LiRbSO4.

ISSN:1042-0150    

DOI:10.1080/10420159608211531

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor