Magnetic tunnel junctions incorporating a cubic GaN x tunnel barrier

Abstract We report on in-plane ( i -) and perpendicularly magnetized ( p -) magnetic tunnel junctions (MTJs) incorporating a metastable cubic GaN x barrier seeded and capped by ultrathin MgO films. The i -MTJs exhibited a tunnel magnetoresistance (TMR) ratio of 72% and a resistance-area product lower than those of the MTJs without GaN x . The p -MTJs showed a TMR ratio of 48% and demonstrated well-defined perpendicular magnetization in the top CoFeB free layer, even with the presence of GaN x . This study indicates that cubic GaN x could facilitate the development of advanced MTJs for memory applications through further improvements in the crystalline quality of GaN x and its interfaces.