GMR of Co/Cu multilayers with reduced hysteresis and low-field response

We present results of a study on optimization of the magnetoresistance (GMR) response in Co/Cu multilayers (MLs) for Cu layer thickness near the second oscillatory peak. Co/Cu MLs with alternating thick (t/sup (1)//sub Co/) and thin (t/sup (2)//sub Co/) Co layers have been prepared in the form of [Cot/sup (1)//sub Co/ /spl Aring//Cu20 /spl Aring//Cot/sup (2)//sub Co/ /spl Aring//Cu20 /spl Aring/]/sub 15/. We have found that the magnetoresistive hysteresis of these MLs is reduced with decreasing t/sup (2)//sub Co/ and has disappeared when t/sup (2)//sub Co/<4.5 /spl Aring/. We have obtained an optimal GMR response with a field sensitivity of 0.13%/0e over a field region of /spl sim/60 Oe centered at /spl sim/50 Oe. This architecture may enable the use of Cu/Co MLs in low-field magnetic sensor applications.