[21a-E216-5~11] 10.3 Spin devices, magnetic memories and storages

▲ [21a-E216-10] Tunneling magnetoresistance effect in magnetic tunneling junction with Ga-based spinel barrier: From first principles

〇Kenji Nawa¹, Yoshio Miura¹ (1.NIMS)

Keywords:Tunneling magnetoresistance effect, Spinel-type oxide, First principles calculations

First principles calculations were performed to investigate tunneling magnetoresistance (TMR) property of spinel-type MgGa₂O₄ (MGO)-based magnetic tunneling junction (MTJ) and results were compared to MgAl₂O₄ (MAO)-based MTJ in terms of barrier-thickness dependence of TMR. Our results indicate that the TMR of MGO-based MTJ increases as the barrier becomes thicker and it reaches 510 % at 24 Å of MGO, whereas that of MAO-based one seems to be independent with regard to the barrier-thickness (TMR= ~76 %). The TMR for both models mainly originates from band-folded Δ₁ coherent tunneling as previously reported but different tendency is found in projection of tunneling density of states (PTDOS) in barrier region. The decay of PTDOS in MAO-based MTJ has almost same ratio in majority and minority states, resulting in the constant TMR against the barrier thickness. On the other hand, in MGO-MTJ, majority evanescent states decay slowly compared to minority ones, thus, this leads to the increase of TMR.