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Rare earth (RE):transition metal (TM) ferrimagnetic alloys continue to attract significant attention for spintronics. This work focuses on the elemental distribution of RE and TM elements throughout the thickness of nominally uniform films and the resulting spatial variations of the magnetization within these layers. Samples of CoFe alloyed with Gd were studied using secondary ion mass spectroscopy, polarized neutron reflectometry, and x-ray resonant magnetic reflectivity. The samples were grown by magnetron co-sputtering to control the RE:TM alloy ratio of the ferrimagnetic layer, which was combined with W and Pt layers as either under or over-layers to create sample structures such as W / Gd x (Co 70 Fe 30) 100 − x / Pt , where x = 0, 8, and 23 at. %. Results show that uniformly deposited thin-films have a significant variation in the distribution of the TM and RE through the film thickness, and this leads to a spatial distribution in the net magnetization profile and a non-uniform Gd magnetization profile within the layer. These findings have implications for the application RE:TM alloys in spintronics as they may impact the perpendicular magnetic anisotropy, the ferrimagnetic compensation temperature, and interfacial spin transport. [ABSTRACT FROM AUTHOR]

We report the SIMS parameters required for the quantitative analysis of Si1-xGex across the range of 0≤x≤1 when using low energy O2+ primary ions at normal incidence. These include the silicon and germanium secondary ion yield [i.e., the measured ion signal (ions/s)] and erosion rate [i.e., the speed at which the material sputters (nm/min)] as a function of x. We show that the ratio Rx of erosion rates, Si1-xGex/Si, at a given x is almost independent of beam energy, implying that the properties of the altered layer are dominated by the interaction of oxygen with silicon. Rx shows an exponential dependence on x. Unsurprisingly, the silicon and germanium secondary ion yields are found to depart somewhat from proportionality to (1-x) and x, respectively, although an approximate linear relationship could be used for quantification across around 30% of the range of x (i.e., a reference material containing Ge fraction x would give reasonably accurate quantification across the range of ±0.15x). Direct comparison of the useful (ion) yields [i.e., the ratio of ion yield to the total number of atoms sputtered for a particular species (ions/atom)] and the sputter yields [i.e., the total number of atoms sputtered per incident primary ion (atoms/ions)] reveals a moderate matrix effect where the former decrease monotonically with increasing x except at the lowest beam energy investigated (250 eV). Here, the useful yield of Ge is found to be invariant with x. At 250 eV, the germanium ion and sputter yields are proportional to x for all x. [ABSTRACT FROM AUTHOR]

This document is an erratum for an article titled "Non-uniform Gd distribution and magnetization profiles within GdCoFe alloy thin films" published in Applied Physics Letters. The erratum corrects an error in the composition of one of the materials used in the original article. The correct composition is Co30Fe70, not Co70Fe30 as previously stated. The legends and caption for Figure 2 have been updated to reflect the correct composition. The erratum states that all other results, discussions, and conclusions in the original article remain the same. [Extracted from the article]

In this paper, we demonstrate why cubic Rashba spin splitting is observed within inverted doped strained germanium (sGe) hetrostructures. Magnetotransport measurements showed beating within the SdH oscillation, with fast Fourier analysis revealing cubic Rashba spin splitting to be present. A cubic Rashba coefficient of β=7.97×10-29 eVm3β=7.97×10-29 eVm3 and a spin-splitting energy of Δ=1.17 meVΔ=1.17 meV were determined. The source of the cubic Rashba spin splitting was identified from a combination of ultra low energy secondary ion mass spectrometry analysis and subsequent band structure modelling using Nextnano3. Ultra-low energy secondary ion mass spectrometry revealed an unintentional, highly B doped near surface region accounted for structure inversion asymmetry, whereas subsequent band structure modelling using Nextnano3 demonstrates how this asymmetric B doping generates structural inversion asymmetry within the sGe QW structure and cubic Rashba spin splitting realized. [ABSTRACT FROM AUTHOR]

The N content of a series of GaNSb samples grown by molecular-beam epitaxy is investigated using high-resolution x-ray diffraction (HRXRD) and secondary-ion mass spectrometry. The N contents determined by the two methods agree well at lower N compositions (x < 0.01), and deviate significantly at larger N contents (x > 0.02). Analysis of the HRXRD-determined lattice constant using Vegard's law, underestimates the N content for high N compositions. The underestimation is found to be up to 24% for x = 0.03. The variation of the lattice parameter with N content is modelled by considering the influence of the density of the interstitial N-Sb complex rising with increasing N content. [ABSTRACT FROM AUTHOR]

The O2+ probe-sample conditions and subsequent data analysis required to obtain high depth resolution SIMS depth profiles from Si1− xGe x/Ge quantum well structures (0.6 ≤ x ≤ 1) are presented. For primary beam energies Ep >500 eV and x approaching 1, a significant decrease in the Ge+ ionisation probability resulted in unrepresentative and unquantifiable depth profiles. For Ep ≤ 500 eV, a monotonic increase in the Ge+ signal with x was observed resulting in profiles representative of the sample structure and enabling x to be found. A depth scale was also established using a point-by-point approach taking into account the local erosion rate, which is a function of x. Both the composition and the thickness of the Si1− xGe x and Ge layers were found to be in excellent agreement with those obtained using X-ray and transmission electron microscopy. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Using an O2+ beam at 90 eV, close to the sputtering threshold, we have obtained depth profiles from superficial monolayers on gold. The samples were polymeric copper phthalocyanine (poly(CuPc)) (C32H12N8Cu)n and Co(II)T(o-NH2)PP (5,10,15,20-tetrakis-(2-aminophenyl) porphyrin-cobalt(II)) (C44H28CoN4) monomolecular layers, deposited on gold films on silicon. The layer thicknesses, determined using atomic force microscopy, were ~4.5 nm for the poly(CuPc) and ~1.8 nm for the Co(II)T(o-NH2)PP. The ion signals monitored included: poly(CuPc) layer: 63Cu+, 65Cu+, 30ON+ and 12 C+; Co(II)T(o-NH2)PP layer: 59Co+, 30ON+ and 12 C+. Comparisons between 90 eV and 235 eV profiles from the layers and bare substrates showed that the monomolecular layers are resolvable at 90 eV and distinct from any surface contamination spike. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The use of Shubnikov-de Haas oscillations for determining effective mass is illustrated by a study of the magnetotransport properties of the two-dimensional hole gas in Si1-xGex (x = 0.13, 0.36, 0.95, 0.98) quantum wells. For some samples the data cannot be fitted to standard theoretical curves in which the scattering of charge carriers is described by the conventional Dingle factor. The reasons for the discrepancies between the experiment the theory are: (i) the effect of spin splitting on the amplitude of the peak in the SdH oscillations; (ii) extra broadening of the Landau levels attributable to an inhomogeneous distribution of the carrier concentration; (iii) the coexistence of short and long-range scattering potentials; and, (iv) population of the second energy level in the quantum well. Ways of calculating the effective hole masses m* for all these cases are presented and values of m* are found for the heterostructures studied here. [ABSTRACT FROM AUTHOR]

In this paper, we report a Hall mobility of one million in a germanium two-dimensional hole gas. The extremely high hole mobility of 1.1?×?106 cm² V-1 s-1 at a carrier sheet density of 3?×?1011?cm-2 was observed at 12?K. This mobility is nearly an order of magnitude higher than any previously reported. From the structural analysis of the material and mobility modeling based on the relaxation time approximation, we attribute this result to the combination of a high purity Ge channel and a very low background impurity level that is achieved from the reduced-pressure chemical vapor deposition growth method. [ABSTRACT FROM AUTHOR]

The thermal stability of thin (110 nm) compressively strained Ge surface channels, grown by reduced-pressure chemical vapor deposition on high quality relaxed Si0.2Ge0.8 reverse-graded buffers, has been investigated using in-situ hydrogen annealing at temperatures up to 650°C. Strain relaxation was observed and found to increase for thicker channels and higher anneal temperatures. For a Ge channel thickness ⩽45 nm, an increased surface roughening was found to dominate the strain relaxation process, which culminated in islanding. For the thicker (⩾45 nm) Ge channels misfit dislocation generation appeared to be the most dominant mechanism. Our results show that low thermal budgets (T < 550°C) should be employed for the fabrication of ~0.65% lattice mismatch strained Ge channels currently being developed for applications in CMOS-based devices and strained Ge-on-insulator platforms. [ABSTRACT FROM AUTHOR]

Enhanced electron cooling is demonstrated in a strained-silicon/superconductor tunnel junction refrigerator of volume 40 μm3. The electron temperature is reduced from 300 mK to 174 mK, with the enhancement over an unstrained silicon control (300 mK-258 mK) being attributed to the smaller electron-phonon coupling in the strained case. Modeling and the resulting predictions of silicon-based cooler performance are presented. Further reductions in the minimum temperature are expected if the junction sub-gap leakage and tunnel resistance can be reduced. However, if only tunnel resistance is reduced, Joule heating is predicted to dominate. [ABSTRACT FROM AUTHOR]

Secondary-ion-mass spectroscopy (SIMS) analysis of insulators using positive primary beams is routinely performed by compensating the induced charge with a coincident electron beam. In the case of SIMS depth profiling, the established method consists of focusing an electron beam into the SIMS crater with a current well in excess of that of the primary ion beam. In this article we used both caesium and oxygen beams to bombard float glass, and intrinsic and doped diamond samples while varying the electron beam current and the area bombarded by electrons. We have studied how the electron beam to primary ion current density ratio modifies the charging conditions. We demonstrate that, for certain insulating and highly resistive materials, defocusing of the electron beam so as to cover the whole of the sample surface and part of the sample holder is extremely effective. It is also observed that the defocused electron beam works efficiently for an electron to primary ion current density ratio less than 1. We attribute this to the enhancement of surface conductivity through the creation of carriers in the conduction band, and observe similar effects when irradiating the surface with a laser diode. The ability to use a defocused electron beam will significantly aid profiling of insulating and highly resistive materials where alignment of the coincident electron and ion beams is problematic. Defocusing of the electron beam also offers the possible advantage of reducing or eliminating localized electron beam damage of certain material surfaces prior to and during profiling. [ABSTRACT FROM AUTHOR]

This article focuses on a study related to the distribution volumes of labelled red blood cells and labelled protein and "F Cells" in intact and splenectomized HbA and HbB type sheep. Red blood cell volume in the sheep has been measured indirectly from Evans' blue dye space and jugular haematocrit and directly by the dilution of labelled red blood cells. Data demonstrate the variability of the red blood cell content of the spleen, a maximum value for which was calculated at about 26% of the total red blood cell volume.

This article focuses on matters related to blood electrolytes in the Australian camel. The blood of sheep and cattle has been studied connection with investigations into the ability of a strain or breed to thrive in different environments. In this study it became apparent that the concentration of electrolytes in the red blood cells of sheep was not the same in all sheep. There seemed to be several distinct patterns of. sodium and potassium concentration. The proportion of the different types in a breed differed from one breed to another and appeared to be associated with their geographical location and the environmental conditions under which they had evolved. The two major patterns have been shown to be simply inherited have been shown to be simply inherited.

Studies the effects of prolonged lithium ingestion on pregnancy in rats. Extent of the initial disturbance caused by the introduction of an ultimately well tolerated lithium dose; Frequency and fate of any pregnancies occurring during the period of regular steady lithium ingestion; Somatic disturbances accompanying lithium introduction.

We demonstrate significant modification of the electron-phonon energy loss rate in a many-valley semiconductor system due to lattice mismatch induced strain. We show that the thermal conductance from the electron system to the phonon bath in strained n+Si, at phonon temperatures between 200 and 480 mK, is more than an order of magnitude lower than that for a similar unstrained sample. [ABSTRACT FROM AUTHOR]

Strain relaxation has been studied in tensile strained silicon layers grown on Si0.5Ge0.5 virtual substrates, for layers many times the critical thickness, using high resolution x-ray diffraction. Layers up to 30 nm thick were found to relax less than 2% by the glide of preexisting 60° dislocations. Relaxation is limited because many of these dislocations dissociate into extended stacking faults that impede the dislocation glide. For thicker layers, nucleated microtwins were observed, which significantly increased relaxation to 14%. All these tensile strained layers are found to be much more stable than layers with comparable compressive strain. [ABSTRACT FROM AUTHOR]

Extreme electron accumulation with sheet density greater than 1013 cm-2 is almost universally present at the surface of indium nitride (InN). Here, x-ray photoemission spectroscopy and secondary ion mass spectrometry are used to show that the surface Fermi level decreases as the Mg concentration increases, with the sheet electron density falling to below 108 cm-2. Surface space-charge calculations indicate that the lowering of the surface Fermi level increases the density of unoccupied donor-type surface states and that these are largely compensated by Mg acceptors in the near-surface hole depletion region rather than by accumulated electrons. This is a significant step towards the realization of InN-based optoelectronic devices. [ABSTRACT FROM AUTHOR]

We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Ultra-low-energy secondary ion mass spectrometry has been used to undertake a structural analysis of GaN-In(x)Ga(1-x)N (x approximately 0.25) quantum wells used in optoelectronic devices. The high resistivity of intrinsic GaN-In(x)Ga(1-x)N restricts the necessary electrical path between the analyzed area and the instrument ground potential resulting in surface charge accumulation. Consequently, unstable and unrepresentative depth profiles tend to be produced. A technique known as optical conductivity enhancement (OCE) has been used during depth profiling to reduce the material resistivity. This creates an electrical path between the sample and holder, eliminating charge build up and resulting in accurate depth profiles., (Copyright 2010 John Wiley & Sons, Ltd.)