34 巻 (2010) 3 号 p. 311-315
We have investigated magnetotransport properties of magnetic tunnel junctions (MTJ) with rock-salt type ZnO(001) or MgO/ZnO(001) barriers by both calculation and experiments. The first-principles transmission calculations based on NEGF method clarifed that the MgO/ZnO barrier had coherent tunneling through Δ1 state such as a conventional MgO(001) barrier. Experimental results revealed that the MTJs with an MgO/ZnO barrier had an MR ratio of 70% at a low resistance-area(RA) product of 0.5Ωμm2. This MR ratio is almost the same as the MgO barrier or higher. The rock-salt type ZnO(001)-based MTJs seem to be suitable for application to the read magnetic heads of hard-disk drives (HDDs) with an areal recording density of over 500Gbits/in2.