Proximity Effect as a Probe of Electronic Correlations and Exchange Field in Dirty Ferromagnet/Superconductor Nanostructures

2009 ◽  
Vol 152-153 ◽  
pp. 457-461
Author(s):  
Larisa A. Terentieva ◽  
Elena L. Parfenova ◽  
Mansur G. Khusainov ◽  
Yurii N. Proshin
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Proximity Effect ◽  
Order Parameter ◽  
Weak Magnetic Field ◽  
Exchange Field ◽  
Electronic Correlations ◽  
Electron Repulsion ◽  
Parameter Symmetry ◽  
Order Parameter Symmetry

We investigate the interplay between the BCS and 2D Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) states in the dirty thin ferromagnetic metal/superconductor (FM/S) nanostructures. For the FM/S bilayers we have derived the dependencies of critical temperature on the FM layer exchange field, electronic correlations and thickness. Moreover, in the corresponding FM/S/FM trilayers we predict two new π phase superconducting states with electron-electron repulsion in the FM layers. The 2D modulated LOFF states are possible in such trilayers only in presence of a weak magnetic field and at suitable parameters of the FM and S layers. On this base we originally propose the method of proximity effect probe the magnitude and sign of the electronic correlations, the order parameter symmetry and exchange fields in various FM layers.

Superconducting Probe of Electronic Correlations and Exchange Field Based on the Proximity Effect in F/S Nanostructures

2012 ◽  
Vol 190 ◽  
pp. 413-416
Author(s):  
M. G. Khusainov ◽  
M. M. Khusainov ◽  
Y. N. Proshin
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Proximity Effect ◽  
Order Parameter ◽  
Weak Magnetic Field ◽  
Exchange Field ◽  
Electron Correlations ◽  
Coupling Constant ◽  
Short Period ◽  
Probe Spectroscopy

The proximity effect and competition between the BCS and LOFF states are studied in the Cooper limit for thin F/S and F/S/F nanostructures, where F is a ferromagnet and S is a superconductor. The dependences of the critical temperature Tc on the exchange field I, electron correlations λf, and the thickness df of the F layer are derived for F/S bilayers and F/S/F trilayers. Two new π-phase superconducting states with electronelectron repulsion in the F layers of F/S/F trilayers are predicted. A 2D LOFF state in F/S/F trilayers is possible only in the presence of a weak magnetic field and the appropriate parameters of the F and S layers. The absence of the suppression of 3D superconductivity in short-period Gd/La superlattices is explained and the electronelectron coupling constant in gadolinium is predicted. A method of superconducting probe spectroscopy based on the proximity effect is proposed for determining the symmetry of the order parameter, the magnitude and sign of electron correlations, and the exchange field in various nanomagnets F.

Consequences of Unconventional Order Parameter Symmetry-High Critical Temperature Structures-

2002 ◽  
Vol T102 (1) ◽  
pp. 51 ◽  
Author(s):  
A. Barone ◽  
J. R. Kirtley ◽  
F. Tafuri ◽  
F. Tafuri ◽  
C. C. Tsuei
Keyword(s):  
Critical Temperature ◽  
Order Parameter ◽  
High Critical Temperature ◽  
Parameter Symmetry ◽  
Order Parameter Symmetry

Example of how an unconventional order parameter symmetry may open new perspectives in the design of HTS Josephson junctions

2002 ◽  
Author(s):  
Francesco Tafuri ◽  
Filomena Lombardi ◽  
F. M. Granozio ◽  
F. Carillo ◽  
Fabrizio Riccia ◽  
...  
Keyword(s):  
Josephson Junctions ◽  
Order Parameter ◽  
Parameter Symmetry ◽  
Order Parameter Symmetry

Anisotropic Order Parameter in Two-Band Superconductivity

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3099-3101 ◽  
Author(s):  
P. Konsin ◽  
N. Kristoffel ◽  
P. Rubin
Keyword(s):  
Order Parameter ◽  
Equation System ◽  
Order Parameters ◽  
Band Model ◽  
Gap Equation ◽  
Narrow Region ◽  
Interband Scattering ◽  
Parameter Symmetry ◽  
Order Parameter Symmetry

A two-overlapping band model of superconductivity with s+d interband scattering is investigated. The gap equation system has been solved numerically. Solutions of pure-d and -s, or of mixed s+d nature are possible. The pure Tcd(μ) or Tcs(μ) curves determine the onset of superconductivity with temperature lowering. In the under- and over-doped region pure-symmetry orderings are preferred. Mixed ordering can exist in a narrow region of μ, becoming narrower with T rising. The peculiarities of the and spectra are reflected in the behaviour of the order parameters. Order parameter symmetry can change with T and μ.

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