Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 34: Superconductivity: Heterostructures

TT 34.4: Talk

Tuesday, April 1, 2014, 12:15–12:30, HSZ 201

Proximity effect in superconductor/conical magnet/ferromag-net heterostructures — •Daniel Fritsch and James F. Annett — H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom

At the interface between a superconductor and a ferromagnetic metal spin-singlet Cooper pairs can penetrate into the ferromagnetic part of the heterostructure with an oscillating and decaying spin-singlet Cooper pair density. However, if the interface allows for a spin-mixing effect, equal-spin spin-triplet Cooper pairs can be generated that can penetrate much further into the ferromagnetic part of the heterostructure, known as the long-range proximity effect [1]. Here, we present results of spin-mixing based on self-consistent solutions of the microscopic Bogoliubov-de Gennes equations incorporating a tight-binding model. In particular, we include a conical magnet into our model heterostructure to generate the spin-triplet Cooper pairs and analyse the influence of conical and ferromagnetic layer thickness on the unequal-spin and equal-spin spin-triplet pairing correlations. It will be shown that, in agreement with experimental observations, a minimum thickness of the conical magnet is necessary to generate a sufficient amount of equal-spin spin-triplet Cooper pairs allowing for the long-range proximity effect [2].

[1] J. W. A. Robinson, J. D. S. Witt, and M. G. Blamire, Science 329, 59 (2010).

[2] D. Fritsch and J. F. Annett, arXiv:1311.3278 (2013).