Title :
Effect of various additions on upper critical field and irreversibility field of in-situ MgB2 superconducting bulk material
Author :
Bhatia, M. ; Sumption, M.D. ; Collings, E.W.
Author_Institution :
Dept. of Mater. Sci. & Eng., Ohio State Univ., Columbus, OH, USA
fDate :
6/1/2005 12:00:00 AM
Abstract :
The effect of silicon carbide, carbon and metal-diboride (NbB2, ZrB2, and TiB2) additions on the irreversibility field, Hirr and the upper critical field Hc2 of bulk superconducting MgB2 have been studied. Samples with 10 mole % of SiC and C and 7.5% of above named metal diboride additions were made separately by a powder milling and compaction technique along with the control sample. These samples were heat-treated at various schedules and Hc2 and Hirr values were measured. An increase in μoHc2 from 20.5 T for pure sample to more than 33 T and enhancement of μoHirr from 16 T to a maximum of 28 T for SiC doped sample was observed at 4.2 K. For a ZrB2 doped sample 24 T and 28.6 T of μoHirr and μoHc2 respectively we obtained with only 2 K drop in the Tc.
Keywords :
ball milling; doping; heat treatment; magnesium compounds; niobium compounds; superconducting critical field; titanium compounds; type II superconductors; zirconium compounds; MgB2:NbB2; MgB2:TiB2; MgB2:ZrB2; carbon; compaction technique; critical field; heat-treatment; irreversibility field; powder milling; silicon carbide; superconducting bulk material; Alloying; Conductivity; Hafnium; Impurities; Inorganic materials; Organic materials; Scattering; Silicon carbide; Superconducting materials; Zirconium; Irreversibility field; upper critical field;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2005.848792