Spin dependent Andreev reflection in ferromagnetic/insulator/d-wave superconductor ballistic junctions

2004 ◽  
Vol 405 (1) ◽  
pp. 77-83 ◽  
Author(s):  
K. Argyropoulos ◽  
A. Dimoulas
Keyword(s):  
Andreev Reflection ◽  
D Wave

scholarly journals THE PROPERTIES OF THE ANDREEV REFLECTION IN FERROMAGNET-INSULATOR-d WAVE SUPERCONDUCTOR JUNCTION

2000 ◽  
Vol 49 (11) ◽  
pp. 2276
Author(s):  
DONG ZHENG-CHAO ◽  
CHEN GUI-BIN ◽  
XING DING-YU ◽  
DONG JIN-MING
Keyword(s):  
Andreev Reflection ◽  
D Wave

Effect of d-wave pair coupling on evanescent type of Andreev reflection

2014 ◽  
Vol 502 ◽  
pp. 36-40 ◽  
Author(s):  
H. Goudarzi ◽  
M. Khezerlou ◽  
T. Dezhaloud
Keyword(s):  
Andreev Reflection ◽  
Pair Coupling ◽  
D Wave

TEMPERATURE AND DOPING DEPENDENCE OF ANDREEV REFLECTION IN Au/La2-XSrxCuO4 POINT-CONTACT JUNCTIONS

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3472-3479 ◽  
Author(s):  
R. S. GONNELLI ◽  
A. CALZOLARI ◽  
D. DAGHERO ◽  
L. NATALE ◽  
G. A. UMMARINO ◽  
...  
Keyword(s):  
Order Parameter ◽  
Andreev Reflection ◽  
Point Contact ◽  
Pair Formation ◽  
The Other ◽  
High Quality ◽  
The Stability ◽  
Best Fit ◽  
Contact Experiments ◽  
D Wave

We performed point-contact experiments on high-quality La 2-x Sr x CuO 4 polycrystalline samples with 0.116 ≤ x ≤ 0.186 by using very sharp Au tips (~ 2μ m of diameter). In most cases we observed conductance curves indicating the occurrence of Andreev reflection. The stability of the contact allowed us to study the temperature dependence of these curves up to Tc. The well reproducible results give no evidence of a pseudogap even in the underdoped samples. We fitted the curves at various temperatures by using the generalized BTK model by Tanaka and Kashiwaya allowing for different symmetries of the order parameter, and we obtained the best fit in the (s+d)-wave case. All the symmetries give similar values of the isotropic component of the gap Δ is , which, at low temperature, is always greater than the anisotropic one Δ an and has a different behaviour in temperature. In the overdoped region, Δ is obtained from Andreev reflection almost coincides with the gap determined by quasiparticle tunneling or ARPES. In the under-doped regime the Andreev gap decreases with x, while, following recent measurements, the gap measured by ARPES rapidly increases at the lowering of x. These results seem to confirm in LSCO the hypothesis, recently appeared in literature, of the existence of two distinct energy scales, one associated with the pair formation and the other related to the achievement of the phase coherence in the condensate.

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