Title :
High density nanocrystalline MgB2 bulk superconductors with improved pinning
Author :
Gümbel, A. ; Perner, O. ; Eckert, J. ; Fuchs, G. ; Nenkov, K. ; Müller, K.H. ; Schultz, L.
Author_Institution :
Inst. for Metallic Mater., IFW Dresden, Germany
fDate :
6/1/2003 12:00:00 AM
Abstract :
We report on the synthesis of high density nanocrystalline MgB2 bulk samples with improved pinning via mechanical alloying of elemental Mg and B powders at ambient temperatures and hot pressing. The samples exhibit high jc at 20 K and 1 T, and an irreversibility line strongly shifted toward higher fields resulting in Hirr of about 0.8Hc2(T) compared to Hirr(T) of about 0.5Hc2(T) as typically observed for untextured conventional bulk specimens. The improved pinning of this material is attributed to the large number of grain boundaries in the nanocrystalline state.
Keywords :
critical current density (superconductivity); flux pinning; grain boundaries; magnesium compounds; mechanical alloying; nanostructured materials; superconducting critical field; type II superconductors; 1 T; 20 K; MgB2; grain boundaries; high density nanocrystalline MgB2; hot pressing; improved pinning; irreversibility line; mechanical alloying; Alloying; Grain boundaries; Inorganic materials; Milling; Plasma temperature; Powders; Pressing; Superconducting materials; Superconductivity; X-ray scattering;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.812091
