We have developed a nanofabrication technique to facilitate current-perpend
icular-to-plane transport measurements on magnetic multilayer pillar struct
ures with diameters as narrow as 100 nm-a size scale at which the reversal
of individual domains within the ferromagnetic layers may be detected. When
large currents are passed through such pillars, the Oersted field produced
by the current can affect the orientation of the magnetic moments of the l
ayers. In pillars ranging from 250 to 500 nm, a stack of alternating hard a
nd soft ferromagnetic layers can controllably be switched between high and
low resistance states via this mechanism. (C) 2000 American Institute of Ph
ysics. [S0003-6951(00)00503-9].