Interplay of Magnetic and Interplay of Magnetic and Superconducting Proximity effect in Superconducting Proximity effect in F/S hybrid structures F/S hybrid structures Thierry Champel Thierry Champel Collaborators: Tomas Löfwander Matthias Eschrig Institut für Theoretische Festkörperphysik Grenoble 16/03/2006
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Interplay of Magnetic and Superconducting Proximity effect in F/S hybrid structures
Interplay of Magnetic and Superconducting Proximity effect in F/S hybrid structures. Thierry Champel. Institut f ü r Theoretische Festk ö rperphysik. Collaborators:. Tomas L ö fwander. Matthias Eschrig. Grenoble 16/03/2006. PLAN. S/F PROXIMITY EFFECT. Characteristic features. Motivation. - PowerPoint PPT Presentation
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Interplay of Magnetic and Superconducting Interplay of Magnetic and Superconducting Proximity effect in F/S hybrid structures Proximity effect in F/S hybrid structures
Possibility for a new physics with interesting applications
S/F PROXIMITY EFFECTS/F PROXIMITY EFFECT
Proximity effect: Penetration ofPairing correlations into non-superconducting areas
In F: center of mass momentum of Cooper pair: 2q
Spatial modulation of the pair amplitude in F
if J=0
fS
Dependence on impurities, interface quality, domain state of F, ...Dependence on impurities, interface quality, domain state of F, ...
leakage of pairs = influence on TC
change of sign = influence on jC in Josephson junctions
nanoscale
Some characteristic
features
S/F PROXIMITY EFFECT : SOME CHARACTERISTIC FEATURESS/F PROXIMITY EFFECT : SOME CHARACTERISTIC FEATURES
Tagirov, PRL 1999
Buzdin et al., EPL 1999
Nonmonotonic behavior of Tc(df)
Superconducting switch
Transparency
+
-
FS
dF
for recent th. developments see e.g. Fominov et al., PRB 2002
Th: Buzdin et al. (1991)
FS
dF
F
dFdS
or
Th:
S/F PROXIMITY EFFECT : SOME CHARACTERISTIC FEATURESS/F PROXIMITY EFFECT : SOME CHARACTERISTIC FEATURES
•Ryazanov et al, PRL (2001)• Kontos et al, PRL (2002)• Guichard et al, PRL (2003)• Bauer et al, PRL (2004)
junctions
Critical current Ic of Cu0.47Ni0.53 junctions as a function of the F layer thickness
From Ryazanov et al. (2005)Taken in Buzdin, RMP 77, 935 (2005)
F SS
2dF
Th: Buzdin et al. (1982)
Exp:
MOTIVATION : ROLE OF INHOMOGENEITY OF EXCHANGE FIELD?MOTIVATION : ROLE OF INHOMOGENEITY OF EXCHANGE FIELD?
Theoretical motivation
• S/F wire with a local inhomogeneity of J
• F/S/F trilayer with noncollinear F moments
Bergeret et al., PRL 2001
Volkov et al., PRL 2003
As a result of inhomogeneity: Production of triplet components which penetrate far in F
QUESTIONS:
Why do we have triplet correlations?Under which conditions are long-range triplet components produced?Signatures and consequences on physical quantities?