First-order high-T-c single-layer gradiometers: parasitic effective area compensation and system balance

We have previously reported an anti-parallel two-SQUID coupling scheme whic h can significantly improve the balance of first-order HTS single-layer gra diometers, and therefore improve the device performance in unshielded envir onments. We report on the behaviour of such devices fabricated on 10x10mm(2 ) and 30x10mm(2) STO bicrystal substrates, We present detailed studies of t he balance of such devices, with particular emphasis on the time-dependent behaviour in unshielded environments, and with the device in motion.