Superconducting Magnet System for a Low Temperature Laser Scanning Microscope
Final rept. 1 Jul-30 Nov 2005
WISCONSIN UNIV-MADISON APPLIED SUPERCONDUCTIVITY CENTER
Pagination or Media Count:
The dominant current-limiting mechanism in YBCO CC tapes still occurs at grain boundaries over a wide range of magnetic fields, even when the FWHM of the texture distribution is only 4-5 deg. The LTLSM is one of very few instruments that can directly observe this limitation. Our initial studies with the LTLSM bought with this equipment grant show that the intragrain critical current density crosses over with the intergrain critical current density at fields of about 2T near liquid nitrogen temperature. The local transport current distribution and the Ex,y distribution depend quite strongly on magnetic field. The LTLSM provides a unique capability for studying this subject because it can operate in any magnetic field. Our aim here was to incorporate a 5T superconducting magnetcryostat into our LTLSM system and to be able to measure the magnetic field dependencies of the voltage change response distributions. The system was installed and worked very well, providing direct data on the influence of grain boundaries and other local sources of dissipation.
- Electrooptical and Optoelectronic Devices
- Electricity and Magnetism