Accession Number : ADA461018


Title :   Superconducting Magnet System for a Low Temperature Laser Scanning Microscope


Descriptive Note : Final rept. 1 Jul-30 Nov 2005


Corporate Author : WISCONSIN UNIV-MADISON APPLIED SUPERCONDUCTIVITY CENTER


Personal Author(s) : Larbalestier, David C.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA461018


Report Date : 22 SEP 2006


Pagination or Media Count : 5


Abstract : 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 E(x,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 magnet/cryostat 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.


Descriptors :   *MAGNETIC FIELDS , *SCANNING ELECTRON MICROSCOPES , LOW TEMPERATURE , SUPERCONDUCTORS , CURRENT DENSITY , GRAIN BOUNDARIES , CURRENT LIMITERS


Subject Categories : ELECTROOPTICAL AND OPTOELECTRONIC DEVICES
      ELECTRICITY AND MAGNETISM


Distribution Statement : APPROVED FOR PUBLIC RELEASE