Title :
Processing and grain boundary effects in Nd1-xBa2-x Cu3O7+d superconductors
Author :
McCallum, R.W. ; Yoo, S.I.
Author_Institution :
Iowa State Univ., Ames, IA, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
Nd1-xBa2-xCu3O7+d samples have been prepared with sharp superconducting transitions, with careful attention given to the details of sample preparation. Two causes for broad samples have been observed. The first is sample inhomogeneity, which is more difficult to eliminate than in the YBa2Cu3 O7 case, and the second appears to be associated with site disorder within a homogeneous sample. Very reasonable intragranular critical currents have been obtained in a sample with a small amount of Nd substituted on the Ba sites, but it is not clear if the Nd plays a direct role in flux pinning. Intergranular critical currents are still quite low due to the large grain size in the high-temperature-processed material and the Nd-deficient layer on the grain boundaries
Keywords :
barium compounds; critical currents; flux pinning; grain boundaries; grain size; high-temperature superconductors; materials preparation; neodymium compounds; superconducting transition temperature; Nd-deficient layer; Nd1-xBa2-xCu3O7+d superconductors; flux pinning; grain boundary effects; high temperature superconductors; high-temperature-processed material; homogeneous sample; intragranular critical currents; large grain size; sample inhomogeneity; sharp superconducting transitions; site disorder; Magnetic materials; Magnetization; Neodymium; Powders; Superconducting materials; Superconducting transition temperature; Superconductivity; Temperature dependence; Temperature distribution; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
