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Exploring spin transport and ferromagnetism with Andreev reflection spectroscopy

Sept. 10, 2009 (past)
12:10 p.m. to 1:35 p.m.
60 St. George Street, MP 606
Boris Nadgorny speaker details
Boris Nadgorny

Abstract:


The Point Contact Andreev Reflection (PCAR) technique [ [1] , [2] ] is sensitive to the spin polarization of the current in a ferromagnet (F) interfaced with a superconductor (S).  The main conduction mechanism in such a channel below the superconducting gap is the so-called Andreev reflection process, in which a quasiparticle current is converted into a supercurrent. However, as de Jong and Beenakker pointed out [ [3] ], for the spin-polarized fraction of the current Andreev reflection is prohibited, thus suppressing the conductance below the gap . The current transfer across an F-S interface can be described by a weak coupling Blonder-Tinkham-Klapwijk (BTK) [ [4] ] type model [ [5] ]. I will discuss the application of this technique to spin polarization measurements, determination of spin-diffusion length, and the studies of dilute magnetic semiconducting oxides [ [6] ].

REFERENCES:


[[1]]. R.J. Soulen, Jr. et al., Science , 282 , 85-88 (1998).

[[2]]. S.K. Upadhyay, et al ., Phys. Rev. Lett . 81 , 3247-3250 (1998).

[[3]]. M.J.M. de Jong and C.W.J. Beenakker, Phys. Rev. Lett . 74 , 1657-1660 (1995).

[[4]]. Mazin, AA. Golubov and B. Nadgorny , Journ. Appl. Phys. 89 , 7576 (2001).

[[5]]. G. E. Blonder, M. Tinkham, and T.M. Klapwijk, Phys. Rev. B 25 , 4515 (1982).

[[6] ]. R.P. Panguluri et al, arXiv:0808.1123 (2008).