Large exchange bias and spin pumping in ultrathin IrMn/Co system for spintronic device applications

Few nanometers thick antiferromagnetic/Ferromagnetic bilayer based spintronic devices have emerged as a potential nanostructured bilayer for achieving ultrahigh-speed magnetization switching, low power dissipation, terahertz magnetization dynamics, and are compatible with CMOS technology. The systematic investigation of the exchange bias (EB) in theIr(22)Mn(78)/Co system is performed by varying Co thickness (t(Co)) in the range of 6-20 nm with 10 nm thin Ir22Mn78 layer on top, using longitudinal magneto-optic Kerr effect (L-MOKE) and ferromagnetic resonance (FMR) measurements at room temperature. Here, we report the occurrence of a record high EB field in this bilayer system, which is 13.11 mT (9.04 mT) statically (dynamically) for 6 nm thick of Co. The percentage change of 313.5 % (251.7%) in exchange bias field is found through FMR (MOKE) measurements with respect to t(Co) variation from 20 to 6 nm. Additionally, the spin pumping mechanism is also studied in the above stated material system by using the FMR technique. The observed linear dependence of effective Gilbert's damping with respect to the 1/t(Co)& nbsp;, indicates the occurrence of spin pumping phenomena. The study suggests that tunability of both the exchange interaction and spin pumping behavior in this Ir22Mn78/Co system, makes this system suitable for future antiferromagnetic spintronic devices.