“…By measuring the electrical resistance of isolated Ni wires with diameters between 20 and 40 nm, Giordano and Hong studied the motion of magnetic domain walls [24,25]. Other low temperature techniques which may be adapted to single particle measurements are Hall probe magnetometry [26,27,28], magnetometry based on magnetoresistance [29,30,31] or spin-dependent tunneling with Coulomb blockade [32,33]. At the time of writing, the micro-SQUID technique allows the most detailed study of the magnetization reversal of nanometer-sized particles [34,35,36,37,38,39].…”