We report superconductivity induced in films of the non-superconducting, antiferromagnetic parent material FeTe by low temperature oxygen incorporation in a reversible manner. X-ray absorption shows ...that oxygen doping changes the nominal Fe valence state from 2+ in the non-superconducting state to mainly 3+ in the superconducting state. Thus superconductivity in O doped FeTe occurs in a quite different charge and strain state than the more common FeTe\(_{1-x}\)Se\(_x\). This work also suggests a convenient path for conducting doping experiments in-situ with many measurement techniques.
A combination of 59Co spin‐echo nuclear magnetic resonance (NMR) and dc magnetization measurements have been carried out on two samples of surfactant‐coated Co nanoparticles in disordered assemblies; ...6.5 nm diameter ε‐Co and 12 nm diameter hcp‐Co. The ε‐Co nanoparticles exhibit superparamagnetic behavior with a blocking temperature TB = 70 K, while the hcp‐Co nanoparticles remain ferromagnetic up to room temperature. In addition, the initial susceptibility for the ε‐Co nanoparticles can be described by the Curie–Weiss law with a negative Θ = −158 K. The NMR signal from the hcp‐Co sample is strong at 77 K with no applied magnetic field; the spectra are straightforward and similar to that for bulk hcp Co. However, the NMR signal from the ε‐Co sample is not detectable at 77 K, even with fields up to 7.5 kOe. A NMR signal appears at 4.2 K; the echo amplitude increases dramatically with applied field. The spectra, which must be corrected for T2 effects, are quite broad and characteristic of the small particle size. Due to the broadening, there were no observable spectral features which could be assigned to the two Co sites in crystalline ε‐Co. The results are discussed in the light of interparticle interactions which reduce the initial susceptibility and lead to negative Θ‐values. Estimates are given for the magnetic dipolar and magnetocrystalline anisotropy energies of the particles in both samples.
College students are often unprepared for the job market after graduation resulting in employment lapses or underemployment in terms of minimum wage jobs. Yet limited research exists on how to ...provide effective job search interventions for this unique population of new job entrants balancing academic and job search activities. Therefore, I examined the efficacy of a technology-mediated job search intervention for undergraduate students (N = 112). Drawing on motivation, job search processes, and past intervention theory and research, I tested if an online job search intervention improved: 1) job search self-efficacy, 2) career adapt-ability resources, and 3) job search behavior frequency and quality. Results from the longitudinal intervention design with random assignment to condition did not identify significant increases in self-efficacy, concern, curiosity, confidence, or control from pre-intervention to one month after the intervention. The intervention also reduced the overall frequency of effort, preparatory job search behavior, and active job search behavior. However, exploratory analyses identified a significant concern by curiosity by control interaction on job search behaviors. When participants reported high control, mismatches between concern and curiosity (i.e., low/high, high/low) predicted less effort and fewer preparatory and active job search behaviors. Implications of this study for future research and intervention designs are discussed.
Boredom is an aversive internal state that increases task-irrelevant thinking, decreases task-directed concentration, and hinders task performance. Job seekers often struggle with boredom while ...completing job search tasks. Implementation intentions – goal-directed action plans – might prove an effective means of coping with boredom during task completion. Prior research has incorporated various forms of implementation intentions but has not yet examined which forms are most effective during the job search. Using a laboratory experiment, I randomly assigned 151 undergraduate student participants to one of four conditions: (1) a superordinate goal only, (2) an implementation intention to reduce distraction, (3) an implementation intention to re-direct attention, or (4) a combined implementation intention condition designed to reduce distraction and then re-direct attention. Participants determined whether a series of employment advertisements matched a provided list of general applicant qualifications, and completed measures of affect, distraction, commitment, boredom, sleep behaviors, and demographics. I hypothesized that boredom would negatively associate with task performance and positively associate with negative affect and distraction during task completion. I also predicted that participants with a combined implementation intention would identify advertisements more accurately, more quickly, and while experiencing less cognitive distraction than would participants with a distraction-inhibiting implementation intention, an attention-directing implementation intention, or only a superordinate goal. As predicted, boredom significantly negatively associated with task performance and significantly positively associated with post-task negative affect and distraction during task completion. The predicted effects of conditions for task performance and distraction did not find support. These findings provide important insights into the adaptive formation of implementation intentions specific to the job search, as well as for goal striving more generally. I discuss the theoretical and practical implications of these results, as well as promising opportunities for future research.
We have determined the site selectivity of Ru and Pd dopants in {beta}-phase NiAl. For both transition metal rich and poor compositions, the Ru or Pd dopant goes to the Ni sublattice. The local ...structural disorder introduced by Pd dopants is significantly greater for the Al-rich than for the TM-rich composition. We have also determined the temperature dependence of the x-ray absorption fine structure Debye-Waller term for Ru atoms in stoichiometric RuAl, Ru in NiAl, and Pd in NiAl. We find evidence for large local shear resistance for Ru dopants in NiAl relative to Pd dopants in NiAl. These results are discussed in terms of calculated elastic moduli and cohesive energies of PdAl and RuAl. (c) 2000 The American Physical Society.
Bulk Scandium trifluoride (\(\mathrm{ScF_3}\)) is known for a pronounced negative thermal expansion (NTE) over a wide range of temperature, from \(10~\mathrm{K}~\text{to}~ 1100~\mathrm{K}\). The ...structure of \(\mathrm{ScF_3}\) can be described as an \(\mathrm{ABX_3}\) perovskite with an empty A-site and a space group of Pm-3m. Growing thin films of \(\mathrm{ScF_3}\) allows for tuning the lattice constant, the thermal expansion, and the construction of devices based upon differential thermal expansion. We have investigated the growth of \(\mathrm{ScF_3}\) films on oxide and fluoride substrates using pulsed laser deposition (PLD) This letter describes the successful growth recipe for producing high quality epitaxial \(\mathrm{ScF_3}\) thin films on positive thermal expansion (PTE) lithium fluoride (\(\mathrm{LiF}\)) substrates, at substrate temperature, \(350^{\circ}\mathrm{C}\) with a laser repetition rate of \(1~\mathrm{Hz}\), with an energy per pulse of \(600~\mathrm{mJ}\), under a vacuum of \(1.5\times 10^{-6}~ \mathrm{torr}\), for a growth time of \(6\) hours. However, even for films with excellent epitaxy and sharp peaks along the principal axes, diffraction peaks from certain crystallographic directions are extremely broad, with the example of (\(104\)) reflections, in this work. We attribute this broadening to disorder in the \(\mathrm{F_6}\) octahedral rotations that occur as an attempt to accommodate the large temperature-induced lattice mismatch that results in cooling from the growth temperature for this system of a NTE film mated to a PTE substrate.
The development of a unique on-site graduate degree program in optics is described. The requirements for such a program are discussed along with particular problems related to logistics, ...administration, and staffing. This example should prove relevant to many geographical areas and disciplines other than optics. The development of optics specializations within the framework of either a physics or electrical engineering curriculum is described.
An outbreak of diarrhea due to infection with Cryptosporidium occurred in a day-care center. During a period of 2 months, 23 of 53 (43%) children attending the day-care center and 15 of 104 (14%) ...household contacts had diarrhea. Cryptosporidium oocysts were identified in 13 of 20 (65%) symptomatic children tested compared with three of 27 (11%) asymptomatic children (chi 2 = 12.56, P less than .001). Enteropathogenic bacteria, enteroviruses, rotavirus, and other protozoan parasites were ruled out as the cause of the diarrhea. A history of diarrhea in household contacts was associated with excretion of Cryptosporidium oocysts by the children. Human-to-human transmission of the infection was suggested by the epidemiology.
In this report, it is shown that Cr doped into the bulk and Cr deposited on the surface of Bi2Se3 films produced by molecular beam epitaxy (MBE) have strikingly different effects on both the ...electronic structure and chemical environment.
