Andreev Reflection In Ferromagnet-Superconductor Junctions

The transport properties of a ferromagnet-superconductor (FS) junction are studied in a scattering formulation. Andreev reflection at the FS interface is strongly affected by the exchange interaction in the ferromagnet. The conductance G_FS of a ballistic point contact between F and S can be both larger or smaller than the value G_FN with the superconductor in the normal state, depending on the ratio of the exchange and Fermi energies. If the ferromagnet contains a tunnel barrier (I), the conductance G_FIFS exhibits resonances which do not vanish in linear response -- in contrast to the Tomasch oscillations for non-ferromagnetic materials.Comment: 8 pages, RevTeX v3.0, including 3 encapsulated postscript figures; [2017: figures included in text

Josephson currents through spin-active interfaces

The Josephson coupling of two isotropic s-wave superconductors through a small, magnetically active junction is studied. This is done as a function of junction transparency and of the degree of spin-mixing occurring in the barrier. In the tunneling limit, the critical current shows an anomalous 1/T temperature dependence at low temperatures and for certain magnetic realizations of the junction. The behavior of the Josephson current is governed by Andreev bound states appearing within the superconducting gap and the position of these states in energy is tunable with the magnetic properties of the barrier. This study is done using the equilibrium part of the quasiclassical Zaitsev-Millis-Rainer-Sauls boundary condition for spin-active interfaces and a general solution of the boundary condition is found. This solution is a generalization of the one recently presented by Eschrig [M. Eschrig, Phys. Rev B 61, 9061 (2000)] for spin-conserving interfaces and allows an effective treatment of the problem of a superconductor in proximity to a magnetically active material.Comment: 8 pages + 3 eps figure

English grammar writing

This chapter charts the history of English grammar writing from the first published grammar of 1586 up to the end of the second decade of the 21st century. The first section covers the period up to the latter part of the 19th century, embracing grammars for English as a foreign language as well as key writers such as John Wallis and Lindley Murray. The second section covers the so-called ‘European Scholarly Tradition’ of Henry Sweet and the following generation of linguists, several of whom were the first professors of English in their home countries. The following section turns to the United States and Structuralist and Generative studies of English grammar. The final section completes the story, considering the major ‘families’ of both printed and online grammatical works. A red thread running through the chapter is the question of how and why particular approaches to grammar become ‘successful’

Drug courts’ effects on criminal offending for juveniles and adults.

Drug courts are specialized courts in which court actors collaboratively use the legal and moral authority of the court to monitor drug-involved offenders’ abstinence from drug use via frequent drug testing and compliance with individualized drug treatment programs. The objective of this review was to systematically review quasi-experimental and experimental evaluations of the effectiveness of drug courts in reducing future offending and drug use. The systematic search identified 154 independent, eligible evaluations, 92 evaluations of adult drug courts, 34 of juvenile drug courts, and 28 of drunk-driving (DWI) drug courts. The findings most strongly support the effectiveness of adult drug courts, as even the most rigorous evaluations consistently find reductions in recidivism and these effects generally persist for at least three years. The magnitude of this effect is analogous to a drop in general and drug-related recidivism from 50% for non-participants to approximately 38% for participants. The evidence also suggests that DWI drug courts are effective in reducing recidivism and their effect on recidivism is very similar in magnitude to that of adult drug courts (i.e., a reduction in recidivism of approximately 12 percentage points); yet, some caution is warranted, as the few available experimental evaluations of DWI drug courts do not uniformly support their effectiveness. For juvenile drug courts we find considerably smaller effects on recidivism. The mean effect size for these courts is analogous to a drop in recidivism from 50% for non-participants to roughly 43.5% for participants