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The new compact ICRH antenna (CIA) with low electric field and conjugate-T has been installed in KSTAR. It is essential for studying the effect on the KSTAR plasma of H minority heating as a main ICRH scheme. The TRANSP-TORIC code has been adopted for analyzing the ICRH effect. The calculation using TRANSP-TORIC has been conducted with an additional 1 MW of ICRH power to the KSTAR operation at B0 = 2.0 T. About 75% of the ICRH power has coupled to the H minority heating, and most of the power of H minority heating has contributed to the energy of D majority ions and electrons. The deposited profile of the minority heating power varies with the concentration rate of the H minority ions and shows the possibility of producing energetic particles which appears to the increasing energy of D majority ions. The power of the H minority heating has good coupling to the majority ions in the broad range of 5

The ease of Te sublimation from Bi2Te3-based alloys significantly deteriorates thermoelectric and mechanical properties via the formation of voids. We propose a novel strategy based on atomic layer deposition (ALD) to improve the thermal stability of Bi2Te3-based alloys via the encapsulation of grains with a ZnO layer. Only a few cycles of ZnO ALD over the Bi2Te2.7Se0.3 powders resulted in significant suppression of the generation of pores in Bi2Te2.7Se0.3 extrudates and increased the density even after post-annealing at 500 °C. This is attributed to the suppression of Te sublimation from the extrudates. The ALD coating also enhanced grain refinement in Bi2Te2.7Se0.3 extrudates. Consequently, their mechanical properties were significantly improved by the encapsulation approach. Furthermore, the ALD approach yields a substantial improvement in the figure-of-merit after the post-annealing. Therefore, we believe the proposed approach using ALD will be useful for enhancing the mechanical properties of Bi2Te3-based alloys without sacrificing thermoelectric performance.

Korea Superconducting Tokamak Advanced Research (KSTAR) program has made significant advances in the development of long pulse and high-performance plasma scenarios, utilizing the advantages of the fully superconducting tokamak. Ten years of KSTAR operation have produced outstanding progress in plasma control, extending the operating window of the plasma discharges, and achieving the H-mode up to 1.2 MA in plasma current, up to 90 s at top duration, and up to 2.16 in elongation. The unique features of the KSTAR device also produced a record 30 s long pulse in H-mode operation without an edge-localized-mode (ELM) crash, and progress in the fundamental transport physics through systematic study, using unique diagnostic capabilities. Therefore, the next near-term research focus will be on how to extend the high performance plasmas up to 300 s by overcoming scientific and engineering obstacles to steady state operation. For fusion reactors, the tokamak device needs to sustain a permanent plasma current. It is also known that the bootstrap current should play an important role in the plasma current for an efficient fusion reactor, and its contribution should be over as high as possible. An internal transport barrier discharge based on the reverse shear profile of the safety factor is one of the promising candidates for enhancing the bootstrap current. However, even in reverse shear mode, an additional external off axis current drive (CD) should be provided to control the current profile, as well as to supplement the plasma current. KSTAR has pursued steady state to operation, aiming for a fully non inductive state, based on real time (RT) plasma control by maximizing the long pulse capabilities of the superconducting machine. In order to deposit current at an arbitrary position, the first requirement is to have many highly efficient CD actuators capable of profile diversity. KSTAR has prepared several RF CD portfolios in addition to a conventional on and off axis CD neutral beam injection (NBI) system. The final target of an off axis current drive will be a 4 MW off-axis NB, 8 MW on-axis NB, 6 MW electron cyclotron heating (ECH), and 4 MW radio frequency heating and current drive (RFHCD) (ion cyclotron (IC), lower hybrid (LH), Helicon CD). In addition, as a long-term goal, demonstrating a long pulse core edge compatible plasma in a reactor relevant condition is important in present medium size tokamak, since it is expected to sustain a very high pressure pedestal height plasma using super H-mode, with parallel upgrades of the superconducting toroidal field (TF) coils.

The electronic structures of Gd-substituted Bi2−xGdxTe3 single crystals have been investigated by employing synchrotron-radiation spectroscopies, such as soft X-ray absorption spectroscopy (XAS), soft X-ray magnetic circular dichroism (XMCD), photoemission spectroscopy (PES), and scanning photoelectron microscopy (SPEM). SPEM measurements confirm that Gd ions are substituted homogeneously in Bi2−xGdxTe3 crystals. The measured Gd 3d XAS and XMCD spectra provide evidence that the substituted Gd ions are trivalent and magnetic. The hν-dependence of the valence-band (VB) PES spectra are described well by the hν-dependent contributions of the Te 5p and Bi 6p states. A good agreement is found between the measured VB PES spectra of Bi2−xGdxTe3 and the calculated partial densities of states, revealing that the Te 5p states will play an important role in determining the thermoelectric and topological properties of Bi2−xGdxTe3.

By employing soft X-ray magnetic circular dichroism (XMCD), soft X-ray absorption spectroscopy (XAS), and photoemission spectroscopy (PES), we have investigated the electronic structure of the candidate zero-moment half-metallic Mn3Ga. We have studied the ball-milled and annealed Mn3Ga powder samples that exhibit nearly zero magnetization. Mn 2 p XAS revealed that Mn ions in Mn3Ga are nearly divalent for both of the Mn ions having the locally octahedral symmetry and those having the locally tetrahedral symmetry. The measured Mn 2 p XMCD spectrum of Mn3Ga is very similar to that of ferrimagnetic MnFe2O4 having divalent Mn ions. The sum-rule analysis of the Mn 2 p XMCD spectrum shows that both the spin and orbital magnetic moments of Mn ions in Mn3Ga are negligibly small, in agreement with the nearly compensated-ferrimagnetic ground state of Mn3Ga. The valence-band PES spectrum of Mn3Ga agrees well with the calculated density of states, supporting the half-metallic electronic structure of Mn3Ga.

By employing soft X-ray magnetic circular dichroism (XMCD) and soft X-ray absorption spectroscopy (XAS), we have investigated the temperature (T)-dependent valence and spin states of Cr ions in half-metallic ferromagnet CrO2 nanorod powder. The lineshape-analysis of both the Cr 2 p XAS and XMCD spectra of CrO2 reveals that the Cr ions in bulk CrO2 have both Cr 4 + t 2 g 2 ↑ and Cr 3 + t 2 g 3 ↑ valence configurations. This work provides the direct experimental evidence for the Cr 3 + - Cr 4 + mixed-valent states in bulk CrO2 ( Cr 3.8 + ) , demonstrating that the half-metallic ferromagnetism in CrO2 originates from the double-exchange interaction. The T-dependent intensity variation of the Cr 2 p XMCD spectrum agrees well with the bulk magnetization M(T) and the Curie temperature, indicating that the measured Cr 2 p XMCD data represent the intrinsic bulk ferromagnetism in CrO2, and support the above finding of the XMCD lineshape analysis.

We have investigated the angle-dependent orbital and spin magnetic moments of the [Co/Pd] multilayer (ML) films with intervening CoO layers under annealing by employing angle-dependent soft X-ray magnetic circular dichroism (XMCD). After annealing, the orbital magnetic moments of Co ions are found to be enhanced, with the maximum values along the perpendicular direction of [Co/Pd] ML, providing evidence for the origin of the improved perpendicular magnetic anisotropy (PMA) being the interface spin–orbit coupling. The induced Pd polarization was observed after annealing, demonstrating the strong Co-Pd hybridization arising from the Co-Pd alloy formation near the interface. The angle-dependent coercivity follows the 1 / cos θ behavior, suggesting that the magnetization reversal in the hysteresis curve in [Co/Pd] ML occurs mainly through the pinning mechanism.

The electronic structures of the layered rare-earth chalcogenide compounds of CeTe2, PrTe2, and PrTe3, which have the charge-density wave (CDW) transition and possibly the chiral transition, have been investigated by employing soft X-ray absorption spectroscopy (XAS) and angle-resolved photoemission spectroscopy (ARPES). R 3d XAS measurements show that the valence states of Ce and Pr ions are nearly trivalent in all the compounds. Similar band dispersions are observed in their measured ARPES data, but with the band positions in PrTe3 being shifted up in energy compared to those in CeTe2 and PrTe2. These findings suggest that their Te 5p band structures are determined mainly by the 2D interactions in the Te(2)/Te(3) sheets, but with a larger number of holes in the Te 5p bands in PrTe3 than in CeTe2 and PrTe2. The measured constant energy maps of CeTe2, PrTe2, and PrTe3 for high binding energies are similar to one another, reflecting the Te 5p band structures of the Te(2)/Te(3) square nets. In contrast, the Fermi surfaces (FSs) of CeTe2 and PrTe3 exhibit extra features, different from the FS of the ideal Te(2)/Te(3) square nets, which arise from the CDW-induced FS reconstruction in the Te(2)/Te(3) sheets.

Structural and oxygen content changes of hexagonal HoMnO3+δ manganite at the stability boundary in the perovskite phase have been studied by X-ray diffraction and thermogravimetry using in situ oxidation and reduction processes at elevated temperatures in oxygen and air. The oxygen storage properties during structural transformation between stoichiometric Hex0 and oxygen-loaded Hex1 phases, transition temperatures and kinetics of the oxygen incorporation and release are reported for materials prepared by the solid-state synthesis and high-impact mechanical milling. Long-term annealing experiments have shown that the Hex0 (δ = 0) → Hex1 (δ ≈ 0.28) phase transition is limited by the surface reaction and nucleation of the new phase for HoMnO3+δ 15MM. The temperatures of Hex0 ↔ Hex1 transitions have been established at 290 °C and 250 °C upon heating and cooling, respectively, at a rate of 0.1° min−1, also indicating that the temperature hysteresis of the transition could possibly be as small as 10 °C in the equilibrium. Ball-milling of HoMnO3+δ has only a small effect on improving the speed of the reduction/oxidation processes in oxygen, but importantly, allowed for considerable oxygen incorporation in air at a temperature range of 220–255 °C after prolonged heating. The Mn 2p XAS results of the Mn valence in oxygen loaded samples support the oxygen content determined by the TG method. The magnetic susceptibility data of the effective Mn valence gave inconclusive results due to dominating magnetism of the Ho3+ ions. Comparison of HoMnO3+δ with previously studied DyMnO3+δ indicates that a tiny increase in the ionic size of lanthanide has a huge effect on the redox properties of hexagonal manganites and that practical properties could be significantly improved by synthesizing the larger average size (Y,Ln)MnO3+δ manganites.

We demonstrate theoretically that the golden phase of SmS ($g$-SmS), a correlated mixed-valent system, exhibits nontrivial surface states with diverse topology. It turns out that this material is an ideal playground to investigate different band topologies in different surface terminations. We have explored surface states on three different (001), (111), and (110) surface terminations. Topological signature in the (001) surface is not apparent due to a hidden Dirac cone inside the bulk-projected bands. In contrast, the (111) surface shows a clear gapless Dirac cone in the gap region, demonstrating the unambiguous topological Kondo nature of $g$-SmS. Most interestingly, the (110) surface exhibits both topological-insulator-type and topological-crystalline-insulator (TCI)-type surface states simultaneously. Two different types of double Dirac cones, Rashba-type and TCI-type, realized on the (001) and (110) surfaces, respectively, are analyzed with the mirror eigenvalues and mirror Chern numbers obtained from the model-independent \emph{ab initio} band calculations., 4 figures, 1 table

The electronic structures of multiferroic oxides of Ba(1-x)Bi(x)Ti(0.9)Fe(0.1)O(3) (0 < x < 0.12) have been investigated by employing photoemission spectroscopy and soft x-ray absorption spectroscopy (XAS). The measured Fe and Ti 2p XAS spectra show that Ti ions are in the Ti4+ states for all x and that Fe ions are Fe2+-Fe3+ mixed-valent for x > 0. The valence states of Fe ions are found to be nearly trivalent for x=0, and decreases with increasing x from being nearly trivalent (v(Fe)~ 3) for x=0 to v(Fe)~ 2.6 for x=0.12. The valence states of both Ti and Ba ions do not change for all x < 0.12. Based on the obtained valence states of Fe ions, the electronic and magnetic properties of Ba(1-x)Bi(x)Ti(0.9)Fe(0.1)O(3) are explored., 9 pages, 3 figures

By employing temperature (T)-dependent soft x-ray magnetic circular dichroism (XMCD) in the Fe and Cr 2p absorption edges, the electronic structures of Li 0.5 FeCr 1.5O4 spinel ferrite, which exhibits magnetization compensation, have been investigated. This work provides evidence that (i) both Fe and Cr ions are trivalent, (ii) most of Fe 3 + ions occupy the A (Td) sites, while Cr 3 + ions occupy the B (Oh) sites, (iii) the magnetic moments of Fe and Cr ions are coupled antiferromagnetically, and (iv) they are reversed at ∼ 255 K. The sum-rule analysis of Fe and Cr 2p XMCD spectra reveals that the orbital magnetic moments of Fe and Cr ions in Li 0.5 FeCr 1.5O4 are much larger than those of metallic Fe and Cr, implying the large spin–orbit coupling and the non-fully occupied t 2 g orbitals of Fe 3 + and Cr 3 + ions. Based on these findings, we have provided a comprehensive model for the electronic and spin configurations of Fe and Cr ions in (Fe)A[ Li 0.5 Cr 1.5]BO4.

The electronic structures of the potential candidate semiconductor nanoparticles for dye-sensitized solar cell (DSSC), such as and , have been investigated by employing X-ray photoemission spectroscopy (XPS). The measured X-ray diffraction patterns show that and samples have the single-phase ilmenite-type structure and the inverse spinel structure, respectively. The measured Zn 2p and Sn 3d core-level XPS spectra reveal that the valence states of Zn and Sn ions are divalent (Zn 2+) and tetravalent (Sn 4+), respectively, in both and . On the other hand, the shallow core-level measurements show that the binding energies of Sn 4d and Zn 3d core levels in are lower than those in . This work provides the information on the valence states of Zn and Sn ions and their chemical bonding in and .

Highly insulated envelope or external insulation systems are being applied in recent energy saving buildings to reduce the heat loss through envelope. Internal insulation systems are applied to most apartments in Korea because they are inexpensive and convenient to construct. However, the internal insulation systems have poor performance because of the heat bridges through structures such as slabs. The external insulation systems have better thermal performance because the heat bridges through the structure are rarely formed. However, it has problems regarding the external insulator separation because of strong winds, spread of fire because of insulator combustion in case of fire, formation of heat bridges through the connectors between structure and external insulation. In this study, the thermal performance of the sandwich insulation system for apartment buildings was evaluated according to the shear connectors and insulation materials.

Evaluation of the thermal performance of a fenestration system during the cooling season is based on heat gains by temperature difference and solar radiation, characterised by thermal transmittance (U-value) and solar heat gain coefficient, respectively. While U-value testing and calculation methods have been long established, solar heat gain coefficient has been evaluated only by calculation under the lack of any established testing method. However, calculation alone cannot yield exact solar heat gain coefficient values for various types of fenestration. To address this problem, this study aims to develop a solar heat gain coefficient apparatus for measuring the energy performance of fenestration in terms of U-value and solar heat gain coefficient, and to evaluate that system. The proposed measurement system can be used in measuring U-values and solar heat gain coefficient values for fenestration with complicated shapes, such as an awning device.

Lately, constructions of large and high-rise buildings are steadily increasing, and various building envelope systems were developed in accordance with this trend. However, insulation methods applied to the building envelope may cause interior condensation, energy loss and discoloration of walls. In this study, ventilated insulation system was applied simultaneously considering conduction, convection and radiation of heat. This research performed a field experiment to evaluate insulating performance comparing ventilated insulation system with non-ventilated insulation system.

The objective of this study was to compare the haemostatic efficacy and foreign body reaction of epinephrine–impregnated cotton pellets with those of epinephrine-impregnated polyurethane (PU) foam cubes in osseous defects created in guinea pigs. Initially, these substances were randomly applied to the osseous defects in guinea pigs for 2 min and blood loss was measured. The animals were then sacrificed 7 weeks later and the degree of foreign body reaction was scored. The data were analysed by the independent-samples Kruskal-Wallis test. Epinephrine-impregnated PU foam cubes showed significantly better haemostatic effect compared to epinephrine–impregnated cotton pellets. The PU foam containing epinephrine specimens elicited significantly less foreign body reaction compared to epinephrine cotton pellets (P

The electronic structures of molecule-based nanoparticles, such as biomineralized Helicobacter pylori ferritin (Hpf), Heme, and RbCo[Fe(CN)6]H2O (RbCoFe) Prussian blue analogue, have been investigated by employing photoemission spectroscopy and soft X-ray absorption spectroscopy. Fe ions are found to be nearly trivalent in Hpf and Heme nanoparticles, which provides evidence that the amount of magnetite (Fe3O4) should be negligible in the Hpf core and that the biomineralization of Fe oxides in the high-Fe-bound-state Hpf core arises from a hematite-like formation. On the other hand, Fe ions are nearly divalent and Co ions are Co2+-Co3+ mixed-valent in RbCoFe. Therefore this finding suggests that the mechanism of the photo-induced transition in RbCoFe Prussian blue analogue is not a simple spin-state transition of Fe2+-Co3+ → Fe3+-Co2+. It is likely that Co2+ ions have the high-spin configuration while Fe2+ ions have the low-spin configuration.

The electronic structures of the magnetic topological insulator candidates of Ce-substituted Bi2–xCexSe3 (x ≤ 0.12) have been investigated through angle-resolved photoemission spectroscopy (ARPES), soft X-ray absorption spectroscopy (XAS), and soft X-ray magnetic circular dichroism (XMCD) measurements on high-quality single crystals. Ce 3d XAS and XMCD measurements provide evidence that the substituted Ce ions in Bi2–xCexSe3 are trivalent and magnetic, confirming the purely magnetic effect of the Ce-substitution. ARPES measurements reveal the formation of an energy gap (Δ) for x > 0, indicating that the finite Δ arises from the broken time-reversal symmetry due to the substituted magnetic Ce impurities.

This paper aims to evaluate the feasibility of using no-insulation High Temperature Superconducting (HTS) coil in persistent current mode system. A HTS coil in persistent current mode system usually includes one or more non-superconducting joints in its circuit. And the current decaying rate of the coil is affected by the resistance of joint in persistent current circuit. If the resistance of joint is large, decaying rate of the current drastically increases. Therefore, reducing the joint resistance of the HTS coil is very important in persistent current mode system. In this paper, the no-insulation HTS coil is suggested as a way to reduce the joint resistance with the embedded parallel contact resistance naturally made by no-insulation winding method. Two small coils are fabricated with insulation and no-insulation winding method, and persistent current mode system experiment of each coil is preformed and analyzed.

By employing soft x-ray absorption spectroscopy (XAS) and soft x-ray magnetic circular dichroism (XMCD), the electronic structures of molecule-based nano bioparticles, such as Helicobacter pylori ferritin (H. pylori ferritin), Heme, -type Prussian Blue (M

A double pancake winding method is widely used to make the superconducting magnet, using high temperature superconductor (HTS) tape. In the double pancake winding method, the joints with contact resistances between double pancake coils are inevitably needed. The electrical joule heating on the contacts causes refrigerant loss during operation. And a space outside the winding, for splices and mechanical support, is more than that for its layer-wound equivalent. In this paper, a double pancake winding method in order to reduce the number of the joints was proposed. Both of the double pancake coils using the conventional winding method and the proposed winding method have been fabricated and tested to make the solution technically feasible in the double pancake winding method. Especially, critical-current tests of the fabricated double pancake coils were conducted in order to show the same performance and confirm contact resistances between double pancake coils.

Summary The purpose of this study was to compare the surface morphology and surface hardness of five materials 24 h after filling, in conditions of 100% humidity, and fetal bovine serum. The five materials were ProRoot Mineral Trioxide Aggregate (MTA), Super-EBA, Intermediate Restorative Materials (IRM), Zinc Oxide Eugenol (ZOE), and Amalgam. The microhardness of these materials was evaluated by Vickers microhardness test, and their morphologies were compared by using scanning electron microscopy (SEM). To evaluate the microhardness, the mixed five materials were measured with Vickers microhardness test. Differences between the experimental groups were analyzed by two-way ANOVA and Duncan's multiple comparison tests. All analyses were performed using the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL). For the microstructural morphological evaluation, the cross cut and root-end cavity prepared surfaces followed by retrograde filling with five different materials were observed under a Scanning Electron Microscope (Steroscan 440; Leica, Cambridge, England) at ×500. To summarize, Super EBA was less influenced by storage medium than the other materials, especially MTA. However, further long-term studies considering other factors, such as biocompatibility (i.e. cellular toxicity) and retention, are needed to be collaborated with these findings in the clinical context. SCANNING 34: 207-214, 2012. © 2011 Wiley Periodicals, Inc.

Electrical system is changing to smart grid which includes the distributed generations with reusable energy sources in these days. The distributed generations are environmentally friendly and have no concern with depletion problem. But dispatching distributed generations can cause an increase of the fault current. Resistive type super conducting fault current limiter is one of the candidates of solution for the large fault problem in smart grid. In this paper, a design method for the wire length of fault current limiter and the result of short circuit test for small scale modules considering system resistance are introduced.

The electronic structures of SrRu 1 − xIr xO 3 films ( 0 ≤ x ≤ 1) have been investigated by employing polarization-dependent soft X-ray absorption spectroscopy. In SrIrO 3, the coherent quasi-particle peak at the Fermi level ( E F) is clearly observed, reflecting the spin-orbit-coupled correlated metallic nature of SrIrO 3. X-ray linear dichroism signals for x = 0 and x = 1 are negligibly weak, demonstrating the pseudo-cubic structure for SrRuO 3 and the strong spin-orbit coupling in SrIrO 3. In contrast, finite linear dichroism is observed for the intermediate x regime, indicating that the narrow d x z ↓ and d y z ↓ bands close to E F are occupied less than the wide d x y ↓ band due to the enhanced in-plane hopping.The electronic structures of SrRu 1 − xIr xO 3 films ( 0 ≤ x ≤ 1) have been investigated by employing polarization-dependent soft X-ray absorption spectroscopy. In SrIrO 3, the coherent quasi-particle peak at the Fermi level ( E F) is clearly observed, reflecting the spin-orbit-coupled correlated metallic nature of SrIrO 3. X-ray linear dichroism signals for x = 0 and x = 1 are negligibly weak, demonstrating the pseudo-cubic structure for SrRuO 3 and the strong spin-orbit coupling in SrIrO 3. In contrast, finite linear dichroism is observed for the intermediate x regime, indicating that the narrow d x z ↓ and d y z ↓ bands close to E F are occupied less than the wide d x y ↓ band due to the enhanced in-plane hopping.

The electronic structures of AgNi1-xCoxO2 (0 les x les 1) delafossite oxides have been investigated by employing photoemission spectroscopy (PES) and X-ray absorption spectroscopy (XAS) in the soft X-ray regime of synchrotron radiation. The Ag 3d core-level PES spectra shift toward the higher binding energy with increasing x, in agreement with the metallic nature for low values of x and the insulating nature for high values of x in AgNi1-xCoxO2 . Further, the Ag 3d core-level PES spectra become more asymmetric with decreasing x, which reflects the larger number of electron-hole pairs in the Ni-rich regime. Valence-band PES spectra reveal that the band width of the occupied Ni 3d states is broader than that of the Co 3d states, implying the larger Ni 3d-O 2p hybridization than the Co 3d-O 2p hybridization. The Co and Ni 2p XAS spectra show that Co ions are in the low-spin Co3+ states for all x, while Ni ions are in the Ni2+-Ni3+ mixed-valent states. The Ni3+ component increases with x.

The electronic structures of Co-based potential thermoelectric (TE) oxides, including \(\hbox{Ca}_3\hbox{Co}_4\hbox{O}_9\) and \(\hbox{Bi}_{2}\hbox{Sr}_{2}\hbox{Co}_2\hbox{O}_{y}\) (y = 8 + δ) single crystals and polycrystalline \(\hbox{Ca}_3\hbox{Co}_2\hbox{O}_6\), have been investigated by employing soft x-ray absorption spectroscopy (XAS) and photoemission spectroscopy (PES). Co 2p XAS measurements show that Co ions are nearly trivalent (\(\hbox{Co}^{3+}\)) in all of these Co-based TE oxides with a small mixture of \(\hbox{Co}^{4+}\) ions in \(\hbox{Bi}_{2}\hbox{Sr}_{2}\hbox{Co}_2\hbox{O}_{y}\). Valence-band PES and O 1s XAS measurements show that the occupied Co 3d states are located at the top of the valence bands and that the lowest unoccupied states have the primarily Co 3d character, respectively. These findings suggest the importance of the Co 3d electronic structures in determining TE properties of these Co-based oxides.

Permalloys were successfully fabricated by melt drag casting in the present study, and their microstructure and consequent magnetic properties have been investigated as a function of Si content. In order to understand the relationship between magnetic properties and Si content, microstructure and texture were observed and phase analysis were performed by TEM. The effective permeability went through a maximum value at Si and then decreased with increasing Si content. Increasing Si content enlarged grain size, which resulted in improvement of permeability. However, over-added Si caused the formation of order phase so that Si added permalloys had the smallest permeability.

Valence states and electronic structures of Cr-doped Nd½A½MnO₃ (NAMO; A=Ca, Sr) manganites have been investigated using x-ray absorption spectroscopy (XAS) and high-resolution photoemission spectroscopy (PES). All the Cr-doped NAMO systems exhibit the clear metallic Fermi edges in the Mn e_g PES spectra near E_F. The spectral intensity at E_F is higher for Cr-doped Nd½Sr½MnO₃ (NSMO) than for Cr-doped Nd½Ca½MnO₃ (NCMO), reflecting the stronger metallic nature for NSMO than for NCMO. The measured Cr 2p XAS spectra are found to be very similar to that of Cr₂O₃, indicating that Cr ions in Cr-doped NAMO are in the trivalent Cr³+ states (t³_(2g)). The Cr 2p XAS data are consistent with the Cr 3d PES spectra located at ~1.3 eV below EF and having no emission near E_F.

The electronic structures of the quenched superconductivity system Y 1-x Pr x Ba 2 Cu 3 O 7-δ (YPrBCO; x = 0, 0.4, 0.8) have been investigated by angle-resolved photoemission spectroscopy (ARPES). With increasing x, the ARPES spectra along Γ → S exhibit a binding energy shift away from E F and a pronounced decrease in the density of electronic states near E F , suggesting an enhanced size of the Fermi wave vector k F from S for x = 0.4, as compared to x = 0. The ARPES results have been compared with the LSDA + U electronic structure calculations incorporating the spin-orbit interaction for PrBa 2 Cu 3 O 7 .

Isothermal solidification of conventional Cu/Sn diffusional couples was performed to form thin (30 µm) joints consisting of Cu-Sn intermetallics. During initial stages of isothermal solidification, both Cu6Sn5 and Cu3Sn phases grow, even though the former is the dominant. After consumption of all available Sn, the Cu3Sn phase grows reactively at the expense of Cu and Cu6Sn5. Finally, we obtain solder joints that consist of only Cu3Sn. Indentation fracture-toughness measurements show that Cu3Sn is superior to Cu6Sn5. Furthermore, indentations of Cu3Sn exhibit the presence of shear bands, which are not observed in Cu6Sn5, implying that the former is more ductile than the latter. Ductile intermetallic-based joints formed by isothermal solidification are promising candidates to form thin (as thin as 5–10 µm or less) solder joints, as they are thermally and thermodynamically stable compared to conventional solder joints. Excess copper in the interconnect provides ductility to the interconnect.

The electronic structure of the electron-doped manganite La0.7Ce0.3MnO3 (LCeMO) has been investigated by performing the band calculations with the local spin-density functional approximation (LSDA), which are then compared to the photoemission spectroscopy (PES) data. In order to investigate the effect of the Mn 3d on-site Coulomb correlation on the electronic structure of LCeMO, we have calculated the Mn 3d partial density of states (PDOS) by performing the LSDA+U calculations. Our calculations show that the Mn 3d on-site Coulomb correlation accounts for the major features in the experimental PES spectra, such as the peak positions and the reduced spectral weight near the Fermi level.

The electronic structures of Pr 1− x Sr x MnO 3 (PSMO; x =1/3, 1/2, 2/3) have been investigated by performing photoemission spectroscopy measurements and the LSDA band-structure calculations. The partial yield spectra and the constant-initial-state spectra near the Pr 4 d absorption edge provide evidence that the Pr ions are nearly trivalent in PSMO. The Pr 4 f and Mn 3 d partial spectral weight (PSW) distributions of PSMO are found to be insensitive to x , reflecting the small overlap between Mn 3 d and Pr 4 f orbitals. The spectrum near the Fermi level exhibits evidence for the metal–insulator transitions with varying x , as well as a charge gap formation for x =1/2.

Highly epitaxial CrSi 2 films were grown on Si(111) substrate by Cr deposition on Si(111)-(7×7) surface at 450°C followed by in situ annealing at 900–1100°C in ultrahigh vacuum. CrSi 2 (001) plane was grown parallel to the Si(111) plane with a CrSi 2 // Si matching face relationship. The valence band (VB photoemission for the 1200-Å-thick CrSi 2 was measured at room temperature and 20 K by using synchrotron radiation (hν=20–120 eV). Overall shapes of the two energy distribution curves (EDC's) were similar. Two peaks were observed in the EDC's corresponding to the bonding and the nonbonding Cr -d states in the CrSi 2. The onset of the VB photoemission measured at 20 K was located at about 0.32 eV below Fermi level, due to the energy band gap opening at low temperature.

A resonant photoemission study has been performed for Pr{sub 1{minus}x}Sr{sub x}MnO{sub 3}thinsp(x=1/3,1/2) and the partial spectral weight (PSW) distributions of both Pr 4f and Mn 3d electrons have been determined. With varying temperature ({ital T}) and {ital x}, metal-insulator transitions are observed in the photoemission data. The Pr ions in Pr{sub 1{minus}x}Sr{sub x}MnO{sub 3} are trivalent, and Pr 4f PSW exhibits a dominant hybridization peak indicating large Pr 4f{minus}Othinsp2p mixing. The Mn 3d PSW at low {ital T} shows a charge gap for x=1/2, and a reduced spectral intensity near E{sub F} for x=1/3, suggesting the localized nature due to the lattice polaron formation. thinsp {copyright} {ital 1999} {ital The American Physical Society}

Mn-based Heusler alloys of NiMnSb and PtMnSb have been predicted to be half-metallic ferromagnetic metals, with 100% spin-polarized conduction electrons at the Fermi level. In this study, the valence-band and Sb 4d core levels of the XMnSb-type Heusler alloys (X = Mi, Pd, Pt) have been investigated using synchrotron-radiation photoemission spectroscopy. Samples were made by melting the appropriate amount of constituent elements in vacuum-sealed quartz tubes at 1100 °C, and subsequent annealing at 600 °C for one week. Photoemission measurements were performed on the Mark V beamline at the Synchrotron Radiation Center at the University of Wisconsin-Madison. Polycrystalline samples were fractured in situ and measured at about 60 K in a vaccum better than 4 × 10−11 Torr. The instrumental resolution of the system is about 0.2 eV at hν=40 eV and about 0.4 eV at hν = 150 eV, respectively. The incident photon flux was monitored by the yield from a gold mesh and all the spectra were normalized to the incident phot...

Pd thin films and Co/Pd multilayered films with progressively thicker Pd underlayers are prepared by physical vapor depositions. Their growth behaviors are investigated using atomic force microscopy and transmission electron microscopy. We observed that a mound occurs on top of each crystallite of (111) oriented polycrystalline Pd films and that the average mound size increases according to the capillary-induced coalescence mechanism. We attribute this observed growth instability to the step barrier which resists step-down diffusion of deposited atoms. We also observed that the mound slopes of Co/Pd multilayers are smaller than those of their Pd underlayers. We suggest that this results from a downhill current driven by the interface energy between the Co and Pd layers.

The valence states and electronic structures of transition-metal ions in spinel Fe1-xCuxCr2S4(0.1lesxles0.5) have been investigated by using scanning photoelectron microscopy (SPEM), photoemission spectroscopy (PES), soft-X-ray absorption spectroscopy (XAS), and soft X-ray magnetic circular dichroism (XMCD). The experimental data have been compared to the calculated density of states (DOS). It is found that the valence states of Cr and Cu ions are nearly trivalent (Cr3+) and monovalent (Cu+), respectively. The Fe 2p XAS spectra of Fe1-xCuxCr2S4 are very similar to that of Fe metal, indicating that Fe 3d states are strongly hybridized to S 3p states. The XMCD measurements for Fe, Cr, and Cu 2p states show evidence that the magnetic moments of Cr ions are antiparallel to those of Fe ions and that Cu ions are weakly polarized parallel to Fe ions. Valence-band PES reveals that Cr 3d states are located at ~-1.5 eV, while Fe 3d states are very broad, in agreement with the calculated DOS. This study indicates that the minority-spin eg states of Fe 3d electrons are located very close to EF, suggesting that the hybridized Fe eg-S 3p states near EF play an important role in determining the transport properties of Fe1-xCuxCr2S4 for xles0.5.

The electronic structures of Sr 2 - x K x FeMoO 6 ( x = 0 , 0.1 , 0.2 ) double perovskites have been investigated by employing photoemission spectroscopy (PES), soft X-ray absorption spectroscopy (XAS), and soft X-ray magnetic circular dichroism (XMCD) near the Fe 2 p absorption edge. The substitution of K + ions for Sr 2 + ions causes the increasing Fe 2 + component in the Fe 2 + – Fe 3 + mixed-valent states, but little difference in the Fe 2p XMCD spectra. As x increases, the photoemission intensity near the Fermi level decreases, which indicates the decreasing carriers and the decreasing bandwidth of the itinerant t 2 g ↓ states.

Electronic structures of AgNi 1 - x Co x O 2 ( 0 ⩽ x ⩽ 1 ) delafossite oxides have been investigated by using photoemission spectroscopy (PES) and soft X-ray absorption spectroscopy (XAS). T 2p XAS ( T = Co , Ni) spectra of AgNi 1 - x Co x O 2 show that the valence states of Co ions are trivalent and do not change with x . In contrast, Ni ions are in the Ni 2 + – Ni 3 + mixed-valent states and the trivalent component increases with increasing x . This finding suggests that the metallic nature of AgNi 1 - x Co x O 2 for low values of x arises from the divalent Ni ions. The valence-band PES study of AgNi 1 - x Co x O 2 reveals that the Ni 3d states are more metallic like than the Co 3d states.

The electronic structure of single crystalline CeNiSn has been investigated using photoemission spectroscopy. The extracted Ce 4f spectrum exhibits three peak structures; the typical Fermi level and 2 eV peaks, and another between them, {approximately}0.9 eV below the Fermi level E{sub F}. The near-E{sub F} peak reflects a substantial Ce 4f-Sn sp hybridization, whereas the 0.9 eV peak arises from the Ce 4f-Ni 3d and Ce 5d-Ni 3d hybridization. A Ni 3d satellite feature is observed about 6 eV below the Ni 3d main band, indicating a strong Ni 3d Coulomb correlation in CeNiSn. The high-resolution photoemission study indicates a finite metallic density of states at E{sub F}, implying a semimetallic ground state. The electronic states near E{sub F} are found to have mixed character from the Sn sp, Ce 5d, Ce 4f, and Ni 3d electrons. Constant-initial-state and constant-final-state yield spectra across the 4d{r_arrow}4f threshold indicate the Ce valence to be close to 3+. {copyright} {ital 1998} {ital The American Physical Society}

Using x‐ray photoelectron spectroscopy (XPS), W 4f core level spectra of electrochromic HxWO3 films have been investigated as a function of the injected charge. W 4f peaks become broader with increasing injected charge. The line shape analysis of W 4f XPS spectra of amorphous HxWO3 films reveals that each spin‐orbit split component consists of two peaks. It is also found that, as the injected charge increases, the intensity of the low binding energy (BE) peaks, the asymmetry factor of core lines, and the intrinsic lifetime width increase systematically. Composite structures of W 4f peaks have been attributed to the existence of the different final states, screened by different numbers of W 5d electrons. The low BE peaks are considered to correspond to the locally screened final states, with one more W 5d electrons than in the ground state, which arise from midgap state conduction electrons near EF. There is also a possibility that a mixture of fine scale phases contributes to composite structures and broader linewidths in HxWO3.

Auger electron spectroscopy, x‐ray photoelectron spectroscopy, and x‐ray diffraction (XRD) were employed to investigate the stoichiometry and texture of the indium‐oxide films. The films were prepared by the reactive evaporation and reactive ion plating of pure indium in an oxygen atmosphere of ∼10−4 Torr. Standard In and In2O3 grains were used to estimate the atomic concentration of the indium‐oxide films and to identify the film orientation. We correlated the electrical and optical properties of the films with their atomic concentration and texture. It was found that the films exhibiting low resistivity have atomic ratios of O to In of 1.29–1.31 and full widths at half‐maximum for (222) XRD peaks of 0.32°–0.34°.

Electronic structure of epitaxial Co films on Pd(111) has been investigated as a function of the Co overlayer thickness, by using angle-resolved photoemission spectroscopy (ARPES). It is found that experimental band structures for Pd(111) and work functions for Co/Pd(111) agree reasonably well with the results of band structure calculations. Compared to Pd(111), valence band ARPES spectra of Co/Pd(111) support the existence of the induced magnetic polarization of Pd atoms near the interface, suggesting large hybridization between Co 3d and Pd 4d states near the interface.