Title :
Multi channel high-Tc scanning SQUID microscope
Author :
Matthews, J. ; Lee, S.Y. ; Wellstood, F.C. ; Gilbertson, A.F. ; Moore, G.E. ; Chatraphorn, S.
Author_Institution :
Center for Supercond. Res., Univ. of Maryland, College Park, MD, USA
fDate :
6/1/2003 12:00:00 AM
Abstract :
We have constructed and tested a multichannel scanning SQUID microscope. An array of up to 8 high-Tc YBCO SQUIDs are mounted on a single chip at the end of a 77 K cold finger. Each SQUID loop measures 30 μm by 60 μm, and the SQUID´s are spaced by about 200 μm. The normal to the surface of the chip (and the SQUID loop) is aligned parallel to the main scanning direction. A vacuum space and a thin (<25 μm) sapphire window separate the SQUID chip from the sample, which is in air at room-temperature. The microscope has been tested by imaging defects in wires and short circuits in computer chips. We discuss the advantages of the multichannel system over the single channel system, as well as some of the obstacles encountered.
Keywords :
SQUIDs; barium compounds; high-temperature superconductors; magnetic sensors; microscopes; superconducting magnets; yttrium compounds; 200 micron; 30 micron; 60 micron; 77 K; YBCO; YBaCuO; cold finger; high-Tc scanning SQUID microscope; magnetic images; multichannel microscope; sapphire window; scanning direction; superconducting magnet wires; vacuum space; Circuit testing; Feedback; Fingers; Microscopy; SQUIDs; Spatial resolution; Superconducting magnets; Superconductivity; Wires; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.813689
