Magnetic properties of L10-Mn57Ga43/Co bilayer films with different Co thicknesses

In order to investigate the interlayer exchange coupling between L10-MnGa and Co bilayer films, we carried out Magneto Optical Kerr Effect (MOKE) measurement and magnetization measurement by VSM for L10-Mn57Ga43 (30 nm)/Co (0-20 nm) bilayer films without annealing and with annealing at 350 °C. The Co thickness dependence of the MOKE signal is explained simply by adding Mn-Ga and Co MOKE signals for the unannealed samples, but not for the annealed samples. We found an inverted Kerr hysteresis curve for the annealed bilayer film with 20 nm Co thickness. This result indicates the antiferromagnetic interlayer exchange coupling between the Mn-Ga and Co layers.