Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session
TT 33.57: Poster
Wednesday, March 28, 2012, 15:00–19:00, Poster B
Josephson-like spin current in junctions composed of antiferromagnets and ferromagnets — •Andreas Moor, Anatoly Volkov, and Konstantin Efetov — Institut für Theoretische Physik III, Ruhr-Universität Bochum, 44780 Bochum, Germany
We study Josephson-like junctions formed by materials with
antiferromagnetic (AF) order parameters. As an antiferromagnet, we consider
a two-band material in which a spin density wave (SDW) arises, e.g., the Fe-based pnictides in the temperature interval Tc≤ T≤ TN, where Tc and TN are the critical
temperatures for the superconducting (S) and antiferromagnetic transitions,
respectively. We have generalized the theory of quasiclassical Green’s functions to two-band superconductors, in which superconducting and antiferromagnetic ordering may coexist, and derived the equations for the quasiclassical Green’s functions. Especially, we are interested in the Josephson-like spin current in the AF/F/AF (F means a ferromagnet) structures, where the short- and long-range components can be identified. This is an analogy with the case of the Josephson current in an S/F/S junction with a nonhomogeneous magnetization where short- and long-range condensate components are induced in the F-layer. However, the analogy is not complete due to the fact that the spin current in AF/F/AF junctions is not constant in space, but oscillates in the ballistic F-layer.
A. Moor, A. F. Volkov, and K. B. Efetov, Phys. Rev. B 83, 134524 (2011);
A. M., A. F. V., and K. B. E., arXiv:1111.5582;
F. S. Bergeret, A. F. Volkov, K. B. Efetov, Rev. Mod. Phys. 77, 1321 (2005);
M. Eschrig, Physics Today, 64, 43 (2011).