Temperature dependence of upper critical fields for clean superconductors of the second kind

1967 ◽  
Vol 202 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Gerhart L�ders
1985 ◽  
Vol 58 ◽  
Author(s):  
Esen E. Alp ◽  
S.K. Malik ◽  
Y. Lepetre ◽  
P.A. Montano ◽  
G.K. Shenoy

ABSTRACTThe structure and superconducting properties of rapidly quenched Zr—Ni and Zr—V alloys have been studied by XRD,EXAFS spectroscopy,TEM,electron diffraction,ED, electrical resistivity and ac susceptibility measurements. Amorphous Zr66Ni34 ribbons quenched with different cooling rates were also examined by flux pinning measurements. Characteristic differences are observed in the flux pinning mechanisms of microcrystalline and amorphous samples. The temperature dependence of upper critical fields have been measured down to 0.4 K and the results are analyzed in terms of WHH theory.


2008 ◽  
Vol 21 (8) ◽  
pp. 085009 ◽  
Author(s):  
Y Shen ◽  
R Gandikota ◽  
R K Singh ◽  
F L Hunte ◽  
J Jaroszynski ◽  
...  

1988 ◽  
Vol 27 (Part 2, No. 6) ◽  
pp. L1094-L1096 ◽  
Author(s):  
Tsutomu Yoshitake ◽  
Tetsuro Satoh ◽  
Yoshimi Kubo ◽  
Takashi Manako ◽  
Hitoshi Igarashi

2014 ◽  
Vol 792 ◽  
pp. 21-26 ◽  
Author(s):  
Tatiana Prikhna ◽  
Michael Eisterer ◽  
Wolfgang Gawalek ◽  
Athanasios G. Mamalis ◽  
Artem Kozyrev ◽  
...  

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.


1988 ◽  
Vol 47 (2) ◽  
pp. 209-211 ◽  
Author(s):  
J. N. Li ◽  
K. Kadowaki ◽  
M. J. V. Menken ◽  
Y. K. Huang ◽  
K. Bakker ◽  
...  

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