Spectral Features of the Proximity Effect

We calculate the local density of states (LDOS) of a superconductor-normal metal sandwich at arbitrary impurity concentration. The presence of the superconductor induces a gap in the normal metal spectrum that is proportional to the inverse of the elastic mean free path $l$ for rather clean systems. For a mean free path much shorter than the thickness of the normal metal, we find a gap size proportional to $l$ that approaches the behavior predicted by the Usadel equation (diffusive limit).Comment: LT22 proceeding

A day-night high resolution infrared radiometer employing two-stage radiant cooling Quarterly report, 1 Apr. - 1 Jul. 1967

Test evaluation of radiant cooler for day-night high resolution infrared radiometer, and electronic design of breadboard radiomete

Theory for the electromigration wind force in dilute alloys

A multiple scattering formulation for the electromigration wind force on atoms in dilute alloys is developed. The theory describes electromigration via a vacancy mechanism. The method is used to calculate the wind valence for electromigration in various host metals having a close-packed lattice structure, namely aluminum, the noble metals copper, silver and gold and the $4d$ transition metals. The self-electromigration results for aluminum and the noble metals compare well with experimental data. For the $4d$ metals small wind valences are found, which make these metals attractive candidates for the experimental study of the direct valence.Comment: 18 pages LaTeX, epsfig, 8 figures. to appear in Phys. Rev. B 56 of 15/11/199

Psychosocial distress and health status as risk factors for ten-year major adverse cardiac events and mortality in patients with non-obstructive coronary artery disease

BackgroundWe examined the risk of psychosocial distress, including Type D personality, depressive symptoms, anxiety, positive mood, hostility, and health status fatigue and disease specific and generic quality of life for MACE in patients with non-obstructive coronary artery disease (NOCAD).MethodsIn the Tweesteden mild stenosis (TWIST) study, 546 patients with NOCAD were followed for 10 years to examine the occurrence of cardiac mortality, a major cardiac event, or non-cardiac mortality in the absence of a cardiac event. Cox proportional hazard models were used to examine the impact of psychosocial distress and health status on the occurrence of MACE while adjusting for age, sex, disease severity, and lifestyle covariates.ResultsIn total 19% of the patients (mean age baseline = 61, SD 9 years; 52% women) experienced MACE, with a lower risk for women compared to men. Positive mood (HR 0.97, 95%CI 0.95–1.00), fatigue (HR 1.03, 95%CI 1.00–1.06), and physical limitation (HR 0.99, 95%CI 0.98–1.00) were associated with MACE in adjusted models. No significant interactions between sex and psychosocial factors were present. Depressive symptoms were predictive of MACE, but no longer after adjustment.ConclusionsIn patients with NOCAD fatigue, low positive mood, and a lower physical limitation score were associated with MACE, without marked sex differences. Type D personality, psychosocial factors, and health status were not predictive of adverse outcomes. Reducing psychosocial distress is a valid intervention goal by itself, though it is less likely to affect MACE in patients with NOCAD

Reorientation of magnetic anisotropy in epitaxial cobalt ferrite thin films

Spin reorientation has been observed in CoFe2O4 thin single crystalline films epitaxially grown on (100) MgO substrate upon varying the film thickness. The critical thickness for such a spin-reorientation transition was estimated to be 300 nm. The reorientation is driven by a structural transition in the film from a tetragonal to cubic symmetry. At low thickness, the in-plane tensile stress induces a tetragonal distortion of the lattice that generates a perpendicular anisotropy, large enough to overcome the shape anisotropy and to stabilize the magnetization easy axis out of plane. However, in thicker films, the lattice relaxation toward the cubic structure of the bulk allows the shape anisotropy to force the magnetization to be in plane aligned

Parent-Adolescent Discrepancies Regarding Adolescents' Peer-Related Loneliness:Associations with Adolescent Adjustment

Because loneliness is a subjective experience, it is often examined using self-reports. Yet, researchers have started to use other-reports to examine loneliness. As previous research suggests that discrepancies between self- and other views might have important implications for adolescents' mental health, the current study examines discrepancies in multi-informant reports on adolescents' loneliness in relation with prosocial behavior, aggression, and adolescents' parent-related loneliness. The sample consisted of 374 mother-adolescent dyads and 318 father-adolescent dyads (41.80% male, M (age) = 15.67 years, SD = 1.25). Results indicated that informants used different reference points to assess adolescents' peer-related loneliness, but were otherwise comparable. Moreover, informant discrepancies were associated with greater adolescents' reported parent-related loneliness. The current study did not provide evidence that discrepancies were related to prosocial or aggressive behavior. The current study adds to the notion that other-reports on loneliness show substantial convergence with self-reports. In addition, this study indicates that the discrepancy between other- and self-reports on loneliness holds valuable information for adolescent socio-emotional adjustment.</p

Andreev Bound States and Self-Consistent Gap Functions for SNS and SNSNS Systems

Andreev bound states in clean, ballistic SNS and SNSNS junctions are calculated exactly and by using the Andreev approximation (AA). The AA appears to break down for junctions with transverse dimensions chosen such that the motion in the longitudinal direction is very slow. The doubly degenerate states typical for the traveling waves found in the AA are replaced by two standing waves in the exact treatment and the degeneracy is lifted. A multiple-scattering Green's function formalism is used, from which the states are found through the local density of states. The scattering by the interfaces in any layered system of ballistic normal metals and clean superconducting materials is taken into account exactly. The formalism allows, in addition, for a self-consistent determination of the gap function. In the numerical calculations the pairing coupling constant for aluminum is used. Various features of the proximity effect are shown

Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6

We have investigated the proximity effect between a superconductor (Nb) and a 'Heavy Fermion' system (CeCu_6) by measuring critical temperatures $T_c$ and parallel critical fields H_{c2}^{\parallel}(T) of Nb films with varying thickness deposited on 75 nm thick films of CeCu_6, and comparing the results with the behavior of similar films deposited on the normal metal Cu. For Nb on CeCu_6 we find a strong decrease of T_c with decreasing Nb thickness and a finite critical thickness of the order of 10 nm. Also, dimensional crossovers in H_{c2}^{\parallel}(T) are completely absent, in strong contrast with Nb/Cu. Analysis of the data by a proximity effect model based on the Takahashi-Tachiki theory shows that the data can be explained by taking into account both the high effective mass (or low electronic diffusion constant), {\it and} the large density of states at the Fermi energy which characterize the Heavy Fermion metal.Comment: 7 pages, 2 figure. Manuscript has been submitted to a refereed journa

Impurity band in clean superconducting weak links

Weak impurity scattering produces a narrow band with a finite density of states near the phase difference $\phi =\pi$ in the mid-gap energy spectrum of a macroscopic superconducting weak link. The equivalent distribution of transmission coefficients of various cunducting quantum channels is found.Comment: 4 pages, 4 figures, changed conten