High field scanning hall probe imaging of high temperature superconductors

Power Applications of high temperature superconductors (HTS) are emerging r apidly towards the market place, While first generation Bi2Sr2Ca2Cu3O10 (BS CCO) powder in tube (PIT) conductors are already used in the industrial sec tor (magnet inserts, transformers and power transmission cables), second ge neration Y1Ba2Cu3O7-delta (YBCO) coated conductors are being developed whic h promise even greater performance, particularly For applications which req uire high magnetic fields. Along with the development of these materials, advances in characterization techniques have enabled detailed studies of the associated loss mechanisms . In particular, magnetic imaging techniques (both scanning hall probe nod magneto optics (MO)) have been able to establish the pattern of current flo w within the samples, allowing study of grain boundary efficiency, current homogeneity and filament interconnection in multifilamentary PIT tapes. How ever, as the technology moves towards high field applications, high-field m agnetic imaging is required. Presently MO is inherently limited to low fiel ds (<0.1 T) and for this reason we have recently focused on the development of a high resolution scanning hall probe device to work in high magnetic f ields. We present data showing bow the current pattern evolves in the prese nce of high magnetic field for various samples and discuss the implications for the future development of HTS conductors.