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We report on modifications of 280-nm thin polycrystalline CrN layers caused by vanadium ion implantation. The CrN layers were deposited at 150°C by d.c. reactive sputtering on Si(100) wafers and then implanted at room temperature with 80-keV V+ ions to fluences of 1×1017 and 2×1017 ions/cm2. Rutherford backscattering spectroscopy, cross-sectional transmission electron microscopy, and X-ray diffraction were used to characterize changes in the structural properties of the films. Their optical and electrical properties were analyzed by infrared spectroscopy in reflection mode and electrical resistivity measurements. CrN was found to keep its cubic structure under the conditions of vanadium ion implantation used here. The initially partially non-metallic CrN layer displays metallic character under implantation, which may be related to the possible formation of Cr1−x V x N. [ABSTRACT FROM AUTHOR]

Implanting photoactive ions into quartz or silica is a simple and efficient way to tune the luminescence light used for various optoelectronic applications. However, such ion implantation damages or even destroys the crystalline order in quartz. We report here on cathodoluminescence of α-quartz after 175 keV Rb-ion implantation and epitaxial growth when annealing the samples in air or 18 O 2. In the cathodoluminescence spectra taken at room temperature, five bands were identified. In addition to three intrinsic bands at 2.40, 2.79, and 4.30 eV, which are related to the quartz and/or silica matrix, two strong violet sub-bands at 3.25 and 3.65 eV were observed, which appear to be strongly correlated with the presence of alkali ions and/or the degree of epitaxy of the matrix. Their properties and origin are discussed in relation to similar bands observed after Ba, Ge, and Na ion implantation. [ABSTRACT FROM AUTHOR]

The neutron-deficient nucleus68As was populated at high spin in two experiments using the reaction40Ca(32S, 3pn) at beam energies of 105 and 95 MeV. A self-supporting and a gold-backed, highly enriched40Ca target were used. Gamma rays were detected with the EUROBALL array, combined with the charged-particle detector array EUCLIDES and the Neutron Wall. The68As level scheme was considerably extended, especially at negative parity and many previous spin-parity assignments were confirmed or rejected. The total-Routhian-surface (TRS) calculations find shape coexistence and ? softness for the negative- and positive-parity states, respectively. [ABSTRACT FROM AUTHOR]

The known level energies, electromagnetic moments and decay probabilities of high-spin states in the N = 46 isotones 86Zr, 87Nb, 88Mo, 89Tc, and 90Ru are interpreted within the shell model. The single-particle space was truncated to the p1/2 and g9/2 orbits (relative to the 88Sr core) and the single-particle energies and empirical two-body matrix elements derived by Gross and Frenkel were used in the calculations. Based on the generally good success of this approach, energies and decay properties of the yrast spectra in 90Ru and 91Rh are predicted. [ABSTRACT FROM AUTHOR]

Subpicosecond lifetimes of high spin states in the rotational nuclei 73Se, 74Se and 74Br have been measured using the 58Ni +19F compound reaction and the Doppler Shift Attenuation method. Six EUROBALL Cluster detectors arranged in cube geometry allowed us to select the relevant transitions in γγ coincidence mode. The high counting statistics achieved in this setup also facilitated the determination of average sidefeeding times, which were found to agree rather well with the results of Monte-Carlo calculations of the particle and γ-ray evaporation process. The deduced quadrupole strengths and deformations are compared with the results of previous measurements and the predictions of Cranked Shell Model calculations. In 74Br, a large and constant prolate deformation of β2= 0.37(1) was found for the presumed 4+ and 3− two-quasiparticle bands. [ABSTRACT FROM AUTHOR]

The magnetic moments of the 12+ and 11− yrast states in 94Ru and of the 25/2−, 29/2+, and 35/2+ levels in 95Rh have been measured via the IMPAD technique. The nuclei were produced in the reaction 58Ni +40Ca and recoil-implanted into polarized Ni and Fe hosts. The g-factors were deduced from the measured time-integral Larmor precessions. The comparison between the experimental results and large-scale shell model calculations suggests that the 12+ and 11− states in 94Ru and the 25/2− level in 95Rh are pure proton states whereas the 29/2+ and 35/2+ states in 95Rh contain a neutron excitation across the N=50 shell gap. This interpretation supports the conclusion drawn from recent lifetime measurements. [ABSTRACT FROM AUTHOR]

The electric hyperfine interaction of ion beam implanted 111In and 111Cd probe atoms in sapphire (Al2O3) single crystals has been investigated using perturbed angular correlation spectroscopy. For both probe atoms the same distinctive electric field gradient was found, indicating that nearly all the implanted probe atoms form a stable substitutional configuration in the temperature range between 77 K and 873 K on the aluminum sublattice. A comparative study between 111In and 111Cd-measurements points to a dynamic interaction initiated by the electron-capture of 111In(EC)111Cd similar to In2O3 and La2O3. Size and orientation of the EFG are discussed in comparison to experimental results in Cr2O3 single crystals. [ABSTRACT FROM AUTHOR]

We report on the results of Perturbed Angular Correlation measurements in polycrystalline (Co1-xInx)1-δO samples (x = 0.04 and 0.8 at.%) using ion-implanted 111In tracers. The temperature and the oxygen activity (adjusted via a CO/CO2 mixture) were chosen in such a way as to be able to observe defect trapping and detrapping in thermal equilibrium. The results are compared with those obtained for (Co1-xInx)1-δO (x= 0.04 at.%) rapidly cooled to 350 K and for CoO. [ABSTRACT FROM AUTHOR]

The temperature dependence of the hyperfine parameters in SrHfO3 powder samples has been investigated by means of Perturbed Angular Correlation spectroscopy using implanted 111In probes. Three quadrupole interactions have been established, with the largest fraction showing a pronounced dynamic interaction. We assign this fraction to 111In / 111Cd probe atoms on substitutional Hf sites. The temperature dependence of the dynamic interaction has been associated to the Pnma↔Imma phase transition at ∼700 K. We discuss the results in relation to those obtained for 181Hf / 111Ta-probes in AHfO3 (A=Ba, Sr, Ca) and for 111In / 111Cd-probes in PbZrO3 and BaTiO3. [ABSTRACT FROM AUTHOR]

In the neutron deficient isotopes 104,105In lifetimes of high spin states in the range from 0.5 ps to 600 ps have been measured in a coincidence recoil distance Doppler shift (RDDS) experiment. By combining the Doppler shift attenuation (DSA) and RDDS methods at few μm flight distances, the problem of delayed feeding has been avoided and very short lifetimes in the range 0.5–0.8 ps have been determined. Shell model calculations with strong restrictions for the neutron orbitals reveal good agreement with experimental level energies and still fair agreement for most measured B(M1) and B(E2) values. [ABSTRACT FROM AUTHOR]

We have applied the technique of direct laser synthesis to the hydrogen–titanium system. Large amounts of hydrogen are incorporated into the sample surface by laser irradiating the samples in a hydrogen atmosphere at elevated gas pressures. The process of “laser hydriding” leads to the formation of TiH2 and the amount of incorporated hydrogen was found to be independent of the hydrogen gas pressure. Similarities to the laser nitriding process are briefly discussed and the results are interpreted with the help of thermodynamic simulations of the laser–material interaction. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Bilayers of polycrystalline Co(37 nm)/Fe(37 nm) were deposited onto Si wafers via electron-gun evaporation and irradiated at room temperature with 200 kev Xe+ ions to fluences of 5 × 1014-1 × 1016/cm². The magneto-optical Kerr effect, Rutherford backscattering spectroscopy and x-ray diffraction were used to characterize the magnetization and microstructure of the films. Xe fluences of up to 5 × 1015 ions/cm² were found to induce a four-fold magnetic anisotropy in the originally isotropic films, as a consequence of the phase transformation of hexagonal Co to face-centered-cubic Co caused by ion irradiation. Xe fluences exceeding 7 × 1015 ions/cm² produced a uniaxial magnetic texture, which is explained by strong Co/Fe interface mixing and possibly ion-induced formation of CoFe grains at the interface. [ABSTRACT FROM AUTHOR]

Reports on the solid-phase epitaxial growth of thin amorphous silicon oxide films deposited by electron gun evaporation in single-crystalline alpha-quartz substrates achieved by high-dose Cs(supra +)-ion implantation. Thin amorphous layer produced by silicon-ion implantation on alpha-quartz epitaxially regrown.