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Notes: We have made preliminary measurements of magnetostriction at the surface (∼5 A(ring)) of sputter-cleaned, amorphous ribbon in uhv (3×10−10 Torr). The value obtained λsurfs(approximately-equal-to)−14.8×10−6 is nearly four times the magnitude of the bulk saturation magnetostriction λbulks=−3.8×10−6 of this material Co76Cr4B20. The measurement was based on the spin polarization of the true secondary electrons emitted normally from the surface by a grazing incidence, 2 keV primary electron beam illuminating an area of a few mm2. Most of the low energy secondary electrons are believed to come from a depth of less than 0.5 nm. The spin polarization was measured using a thin film, diffuse-spin-orbit-scattering polarimeter. High quality, reproducible polarization vs. field (P–H) loops were obtained after repeated sputter cleaning and annealing in situ. Magnetostriction is determined by λ(H)= ∫H0d(H)dH where d(H)=4π∂M/∂σ]H is the magnetostrictivity, i.e., the stress sensitivity of magnetization at constant field. The latter was measured by bending the sample in situ to achieve tensile or compressive stresses at the front surface up to 107 Pa. The present effect is in no way related to the stress induced changes in bulk magnetostriction measured by Barandiaran et al. which are three orders of magnitude smaller in Δλ/Δσ.

Notes: The electronic and optical properties of Ge-doped vapor epitaxial indium phosphide were studied. From Hall-effect measurements, it was determined that the Ge-doped material was heavily compensated even for highly doped material. The defects responsible for compensating the InP were investigated by low-temperature photoluminescence measurements at 10 K. Strong acceptor-related transitions at 1.379 and 1.395 eV were observed in the doped material. Deep-level emission at 1.17 eV was also observed in the heavily doped material. The relationship between these bands and compensation is discussed. The observed doping dependence of Ge in InP suggests that self-compensation by native defects may be important in determining the electronic properties of group IV doped III-V compounds in support of recent theoretical predictions.

Notes: Intrinsic viscosity measurements were carried out with a polystyrene (M¯w3.2×106, M¯w/M¯n=1.03) in cyclohexane at temperatures near and including θ down to the point before precipitation occurs. The transition of coil conformation from θ state to the collapse state seems to be relatively smooth. The onset of the collapse is estimated to be at 32.9 °C.

Notes: Deep levels in vapor epitaxial indium phosphide grown in the presence of ammonia were investigated by transient capacitance spectroscopy. A total of three hole traps associated with nitrogen doping was observed with activation energies of 0.21, 0.3, and 0.45 eV. The traps H(0.21) and H(0.3) are tentatively attributed to a nitrogen-impurity complex. Concentrations of deep trapping states as high as 8×1014 cm−3 were observed in the as-grown layers.

Notes: Abstract New isotopic (Rb–Sr, U–Pb zircon and Sm–Nd) and petrological data are presented for part of an extensive Proterozoic mobile belt (locally known as the Rayner Complex) in East Antarctica. Much of the belt is the product of Mid-Proterozoic (∼ 1800–2000 Ma) juvenile crustal formation. Melting of this crust at about 1500 Ma ago produced the felsic magmas from which the dominant orthogneisses of this terrain were subsequently derived. Deformation and transitional granulite-amphibolite facies conditions (which peaked at 750 ± 50°C and 7–8 kbar (0.7–0.8 GPa) produced open to tight folding about E–W axes and syn-tectonic granitoids about 960 Ma ago. Subsequent felsic magmatism occurred at about 770 Ma and not, as has been widely advocated, at 500–550 Ma, which appears to have been a time of widespread upper greenschist facies (400–500°C) metamorphism, localized shearing and faulting.Sm-Nd model ages of 1.65–2.18 Ga disprove a previously favoured hypothesis that the Rayner Complex mostly represents reworked Archaean rocks from the neighbouring craton (Napier Complex). Models that involve rehydration of the Napier Complex are no longer required, since the Rayner Complex was its own source of water. Two episodes of Proterozoic crustal growth are identified, the later of which occurred between about 1200 Ma and 1000 Ma, and was relatively minor. Sedimentation took place only shortly before Late Proterozoic orogenesis.The multiphase history of the Rayner Complex has resulted in complex isotopic behaviour. Three temporally discrete episodes of Pb loss from zircon have been identified, the earliest two of which are responses to the c. 960 Ma and 540 Ma tectonothermal events. Fluid leaching was operative during the later event for there is a good correlation between degree of isotopic discordance and secondary mineral growth. Pb loss during the high-grade event was probably governed by the same process or by lattice annealing. Some zircon suites also document recent Pb loss. Most lower concordia intercepts have no direct geological meaning and are explicable as mixed ages produced by incomplete Pb loss during two or more secondary events. Whereas all zircon separates from the orthogneisses produce U–Pb isotopic alignments, zircons from the only analysed paragneiss produce scattered data, in part reflecting a range of provenance. The 960 Ma event was also associated with the growth of a characteristically low U zircon (∼ 300 μg/g) in rocks of inferred high Zr content.There is ubiquitous evidence for the resetting of Rb–Sr total-rock isochrons. Even samples separated by up to 10 km fail to produce igneous crystallization ages. Minor mineralogical changes produced by the 540 Ma upper greenschist-facies metamorphism were sufficient to almost completely reset some Rb–Sr isochrons and to produce open system conditions on outcrop scale, at least in one location.

Notes: This work investigated the barrier properties of metalorganic chemical-vapor-deposited (CVD) tantalum nitride (TaN) and physical-vapor-deposited (PVD) TaN between Cu and Si. The CVD TaN film had a preferred orientation (200) with a grain size of around 60 nm, while the PVD TaN had a (111) preferred orientation with a grain size of around 20 nm, as determined by transmission electron microscopy (TEM) and x-ray diffraction (XRD) analyses. Degradation study of the Cu/TaN/Si contact system was also performed by sheet resistance measurement, scanning electron microscopy (SEM), XRD, secondary ion mass spectroscopy (SIMS), and shallow junction diodes. These results indicated that the PVD TaN film can act as a better diffusion barrier than the CVD TaN film. The higher thermal stability of PVD TaN than CVD TaN can be accounted by their difference in microstructures. The failure mechanisms of both CVD TaN and PVD TaN films as diffusion barriers between Cu and Si were also discussed. © 1996 American Institute of Physics.