Very large magnetoresistance effects induced by antiparallel magnetization in two ultrathin cobalt films

摘要

Magnetoresistance(MR)and magnetization measurements by SQUID have been performed on Au/Co.Au/Co/Au multilayers in which the two ultrathin cobalt films have perpendicular magnetizations and different coercive fieldsHc1andHc2due to their different thicknesses. The two Co layers are magnetically uncoupled, as shown by their well separated square hysteresis loops. The MR exhibits a plateau for magnetic fieldsHsuch asHc1