Thin layer of MgO as seed layer used in MgO/Co2FeSi Heusler alloy tunnel junctions

This study examines the efficacy of adding a thin seed layer of MgO underneath the Co₂FeSi free layer below the MgO tunnel barrier to induce order in the cubic phase. The magnetic multilayers are grown via magnetron sputtering at room temperature with base pressure of 6.6×10^-7 Pa and vacuum annealed at 360°C for an hour. A current in-plane testing apparatus is employed to determine tunnelling magnetoresistance values. Magnetic hysteresis loops data indicate that the samples have anisotropic magnetization with an easy in-plane direction and the coercivity is inversely proportional to the seed layer thickness.