Enhanced magnetoresistance in perpendicular magnetic tunneling junctions with MgAl₂O₄ barrier

Perpendicular magnetic tunnel junction with MgAl2O4 barrier is investigated. It is found that reactive RF sputtering with O-2 is essential to obtain strong perpendicular magnetic anisotropy and large tunneling magnetoresistance in MgAl2O4-based junctions. An interfacial perpendicular magnetic anisotropy energy density of 2.25 mJ/m(2) is obtained for the samples annealed at 400 C. An enhanced magnetoresistance of 60% has also been achieved. The V-half,V- bias voltage at which tunneling magnetoresistance drops to half of the zero-bias value, is found to be about 1 V, which is substantially higher than that of MgO-based junctions.