This paper presents a comparative first principle study of tunneling magneto resistance (TMR), spin transfer torque (STT) and resistance area (RA) product of magnetic tunnel junctions (MTJ) having different quantum well states in middle of MgO barrier region. We report that such MTJs show enhanced STT and low RA product as compared to only MgO barrier MTJ with maintaining high TMR. Electronic structure of quantum well states adjudicates magnitude of TMR in MTJs. It is found that quantum well states having s-like character allow the transmission of Δ₁ symmetry of Bloch wave whereas d-like character supports to the transmission of Δ₂, Δ_2′, and Δ₅ symmetry. This increases transmission of spin polarized tunneling current with good spin filtering injection efficiency resulting in higher STT. It will produce less heat on applying critical switching current density (J_co), for current induced magnetization reversal by STT phenomenon without breakdown of the barrier.

本文提出了一个比较性的第一性原理研究，即在MgO势垒区中间具有不同量子阱态的磁性隧道结（MTJ）的隧穿磁阻（TMR），自旋传递转矩（STT）和电阻面积（RA）乘积。我们报道，与仅具有高TMR的MgO势垒MTJ相比，此类MTJ显示出增强的STT和低RA产品。量子阱态的电子结构可判断MTJ中TMR的大小。据发现，量子阱各州具有小号样字符允许Δ的传输₁布洛赫的对称波而d样字符支撑到Δ的传输₂，Δ _{2' ，}和Δ ₅对称。这增加了自旋极化隧穿电流的传输，并具有良好的自旋滤波注入效率，从而提高了STT。在施加临界开关电流密度（J _co）时，它将产生较少的热量，从而通过STT现象使电流感应的磁化强度反转，而不会破坏势垒。