Title :
Persistent magnetic flux and mapping of intergranular junctions in melt textured YBa/sub 2/Cu/sub 3/O/sub 7/
Author :
Gomis, V. ; Castello, D. ; Catalan, I. ; Martinez, B. ; Fontcuberta, J. ; Fuertes, A. ; Obradors, X.
Author_Institution :
Inst. de Ciencia de Mater., Campus de la Univ. Autonoma de Barcelona, Spain
fDate :
3/1/1993 12:00:00 AM
Abstract :
Melt-textured superconductors have been prepared with a microstructure characterized by large domains having misaligned growth fronts. An RF mutual inductance microprobe has been developed to identify and characterize the weak-link behavior of the high-angle grain boundaries separating the domains. The mechanisms of flux penetration and trapping in a single-domain sample have been analyzed in a H/sub //c/ configuration at low temperature, 25 K, where J/sub c/ is essentially field independent. A consistent description of flux penetration, isothermal remanence and magnetic hysteresis is reached in the framework of the Bean model. The small value of the lower critical field deduced from this analysis suggests that the Bean-Livingston surface barriers are strongly reduced in melt-textured ceramics as compared to single crystals.<>
Keywords :
X-ray diffraction examination of materials; barium compounds; critical current density (superconductivity); flux flow; flux pinning; grain boundaries; high-temperature superconductors; magnetic domains; magnetic flux; magnetic hysteresis; magnetisation; remanence; scanning electron microscope examination of materials; surface texture; yttrium compounds; 25 K; Bean model; Bean-Livingston surface barriers; RF mutual inductance microprobe; SEM; X-ray diffraction; YBa/sub 2/Cu/sub 3/O/sub 7/; critical current density; critical field; flux penetration mechanism; high-angle grain boundaries; intergranular junction mapping; isothermal remanence; magnetic domains; magnetic hysteresis; melt textured superconductors; melt-textured ceramics; microstructure; persistent magnetic flux; weak-link behavior; Grain boundaries; Inductance; Isothermal processes; Magnetic analysis; Magnetic flux; Microstructure; Radio frequency; Radiofrequency identification; Superconductivity; Temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
