On narrowing of the resistive superconducting transition in applied magnetic fields and positive curvature in Hc2(T) in the (Gd1−xPrx)Ba2Cu3O7−δ system
Iwasaki
H
author
Dalichaouch
Y
author
Markert
J
T
author
Nieva
G
author
Seaman
C
L
author
Maple
M
B
author
1990
The superconducting transition temperature Tc and the temperature dependence of the upper critical field Hc2 were measured resistively on polycrystalline samples in the (Gd1−xPrx)Ba2Cu3O7−δ system. The experimental results reveal that Tc decreases monotonically with increasing x and vanishes at x≈0.49. Whereas Hc2 of a sample with x=0.10 has an almost linear temperature dependence and the superconducting transition broadens with increasing magnetic field, a sample with x=0.45 shows strong positive curvature in the Hc2 versus temperature curve and narrowing of the superconducting transition width with increasing magnetic field. Both phenomena observed in the sample with x=0.45 can be explained qualitatively in terms of a negative exchange interaction between the superconducting charge carriers and the Pr 4f electrons.
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text
Iwasaki_etal1990
Physica C: Superconductivity
Physica C
1990
continuing
periodical
academic journal
169
1-2
146
151