[en] Spin-transfer torque (STT) applications in magnetization switching such as magnetic tunnel junctions (MTJs) have been of popular interest in the development of novel memory technologies. However, the high switching power associated with these is a critical disadvantage in the operation of typical magnesium oxide (MgO)-based STT-MTJs. In this study, an ultra-low switching power, only 10% of the MgO-based MTJs, is achieved by high-purity spin polarization current using a superlattice-barrier MTJ with half-metallic magnets. The resistance-area product of the device is reduced to 0.2 Ω μm², which is less than 10% of that in traditional MgO-based MTJs. The proposed MTJ has a higher performance, including STT and required switching current. A decrease in the switching power could avoid not only the disadvantages of power dissipation but also the device endurance due to lower Joule heating in the proposed MTJs. (paper)