Magnetic tunnel junctions utilizing perpendicularly magnetized MnGa ultrathin films grown on sapphire substrate

Kamata, Naoki*; Mizukami, Shigemi*; Suzuki, Kazuya

Perpendicularly magnetized tetragonal Mn-based alloy thin films are attractive materials as a ferromagnetic electrodes of perpendicular magnetic tunnel junctions (p-MTJs). In this study, we demonstrate the p-MTJs using L10-MnGa ultrathin electrodes grown on the sapphire(r-plane) substrate. We succeeded the growth of single crystalline L10-MnGa ultrathin films on the sapphire(r-plane) substrate by introducing the bcc-Ta/Cr/CoGa hybrid buffer layers between substrate and MnGa layers. In addition, the p-MTJs grown on sapphire substrate exhibited clear TMR of 6-7% at room temperature. These results suggests that new growth technique of single crystalline MnGa ultrathin film will open the development of single crystalline MnGa-based spintronics devices.