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We have investigated point contacts between a superconductor (Nb, AuIn2) and a normal metal (ferromagnetic Co, non-magnetic Cu). The observed Andreev-reflection spectra were analyzed using the modified BTK theory including spin-polarization…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Elina Tuuli , Kurt Gloos

We present measurements of the transport spin polarization of Ni_xFe_{1-x} (0<x<1) using the recently-developed Point Contact Andreev Reflection technique, and compare them with our first principles calculations of the spin polarization for…

We present a systematic analysis of point-contact Andreev reflection (PCAR) spectra for ferromagnetic materials, using both modeling and experimental data. We consider the relationship between ballistic and diffusive transport, the effect…

Strongly Correlated Electrons · Physics 2009-11-10 G. T. Woods , R. J. Soulen , I. I. Mazin. , B. Nadgorny , M. S. Osofsky , J. Sanders , H. Srikanth , W. F. Egelhoff , R. Datla

We investigated the transport properties in a normal metal/ferromagnet/normal metal/superconductor junction based on semi-Dirac materials with inverted energy gap. With a scattering matrix approach, we show that the electron transport in…

Superconductivity · Physics 2023-11-03 Yupeng Huang , R. Shen

We study the transport properties of a voltage biased contact between two spin-split superconductors separated by an insulating barrier of arbitrary transparency. At low transparency, the contribution of multiple Andreev reflections leads…

Superconductivity · Physics 2020-01-15 Bo Lu , Pablo Burset , Yukio Tanaka

We report on transport measurements on Nb/Al/Gd/Al/Nb junctions.Bulk Gadolinium is a weakly polarized ferromagnet (5-7%), and is present in the junction in granular form (superparamagnet). We show that Andreev reflection is strongly…

Superconductivity · Physics 2007-05-23 O. Bourgeois , P. Gandit , J. Lesueur , R. Mélin , A. Sulpice , X. Grison , J. Chaussy

We report temperature dependent Andreev reflection measurements of Co/ Y$_{1}$Ba$_{2}$Cu$_{3}$O$_{7-\delta}$ (YBCO) heterostructure samples with junction areas of 1 $\mu$m diameter. Modelling of the 5-70 K conductivity data according to a…

Superconductivity · Physics 2009-03-24 N. Ghosh , J. Barzola Quiquia , Q. Xu , G. Biehne , H. Hochmuth , M. Lorenz M. Grundmann , H. Schmidt

We discuss the properties of a ferromagnet - superconductor heterostructure on the basis of a Hubbard model featuring exchange splitting in the ferromagnet and electron - electron attraction in the superconductor. We have solved the spin -…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. Krawiec , B. L. Gyorffy , J. F. Annett

We show that noncollinear Andreev reflections can be induced at interfaces of semiconductor nanowires with spin-orbit coupling, Zeeman splitting and proximity-induced superconductivity. In a noncollinear local Andreev reflection, the spin…

Superconductivity · Physics 2014-11-27 B. H. Wu , W. Yi , J. C. Cao , G. -C. Guo

The correlation between the magnetic moment in ferromagnetic alloys and the tunneling spin polarization in ferromagnet-insulator-superconductor tunneling experiments has been a mystery. The measured spin polarization for Fe, Co, Ni, and…

Materials Science · Physics 2009-10-31 Tat-Sang Choy , Jian Chen , Selman Hershfield

We analyze the change in the resistance of a junction between a diffusive ferromagnetic (F) wire and normal metal electrode, due to the onset of superconductivity (S) in the latter and a double Andreev scattering process leading to a…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Vladimir I. Fal'ko , A. F. Volkov , C. Lambert

In the "ballistic" regime, the transport across a normal metal (N)/superconductor (S) point-contact is dominated by a quantum process called Andreev reflection. Andreev reflection causes an enhancement of the conductance below the…

Superconductivity · Physics 2021-10-04 Ritesh Kumar , Goutam Sheet

The accurate and proper form of electron-hole excitations and corresponding Dirac-like spinors of monolayer molybdenum disulfide superconductor are exactly obtained. Andreev reflection and resulting subgap conductance in a $MoS_2$-based…

Mesoscale and Nanoscale Physics · Physics 2017-02-01 H. Goudarzi , M. Khezerlou , S. F. Ebadzadeh

We study Andreev reflection at an interface between a half metal and a superconductor with spin-orbit interaction. While the absence of minority carriers in the half metal makes singlet Andreev reflection impossible, the spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Mathias Duckheim , Piet W. Brouwer

Andreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions have…

We theoretically analyzed the Andreev reflection in ferromagnetic metal/nonmagnetic metal/superconductor double junctions with special attention to the electron interference effect in the nonmagnetic metal layer. We showed that the…

Mesoscale and Nanoscale Physics · Physics 2009-06-29 Hiroyuki Ohtori , Hiroshi Imamura

We investigate the subgap transport properties of a S-F-Ne structure. Here S (Ne) is a superconducting (normal) electrode, and F is either a ferromagnet or a normal wire in the presence of an exchange or a spin- splitting Zeeman field…

Superconductivity · Physics 2015-06-04 A. Ozaeta , A. S. Vasenko , F. W. J. Hekking , F. S. Bergeret

We report on electronic transport properties of mesoscopic superconductor-ferromagnet spin-valve structures. Two ferromagnetic iron leads form planar tunnel contacts to a superconducting aluminum wire, where the distance of the two contacts…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 D. Beckmann , H. v. Löhneysen

We carried out Point Contact Andreev Reflection (PCAR) spin spectroscopy measurements on epitaxially-grown ferromagnetic In1-xMnxSb epilayers with a Curie temperature of ~9K. The spin sensitivity of PCAR in this material was demonstrated by…

Superconductivity · Physics 2009-11-10 R. P. Panguluri , B. Nadgorny , T. Wojtowicz , W. L. Lim , X. Liu , J. K. Furdyna

We have measured the non-local resistance of aluminum-iron spin-valve structures fabricated by e-beam lithography and shadow evaporation. The sample geometry consists of an aluminum bar with two or more ferromagnetic wires forming point…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 D. Beckmann , H. B. Weber , H. v. Löhneysen