为了研究势垒对铁磁/绝缘层/半导体/绝缘层/铁磁(FM/I/SM/I/FM)双隧道结中自旋相关电子输运特性的影响,提出了在半导体层厚度合适的情况下,非对称势垒对于提高平行结构磁性双隧道结的自旋注入效率SIE(spininjection efficiency)更具优势。数值计算结果表明,当两势垒强度的比率达到合适数值时双结的SIE和隧穿磁电阻TMR(tunneling magnetore resistance)都将达到最大,这给提高从铁磁到半导体的SIE带来新选择。研究还表明,非对称势垒结构磁性隧道结中增大铁磁交换能对提高SIE和TMR都是有益的,而且铁磁交换能的增加对SIE的提高要比对TMR的提高更显著。
To investigate the influence of the potential barrier in spin-dependent transport in FM/I/SM/I/ FM (ferromagnet/insulating barrier/semiconductor/insulating barrier/ferromagnet) magnetic double tunnel junctions, it was proposed that asymmetric potential barrier played a superior role in enhancing SIE (spin injection efficiency) in parallel structure of the magnetic double tunnel junctions when the layer of semiconductor was suitable. According to the numerical calculation, SIE or TMR(tunneling magnetore resistance) could reach a maximum when the ratio of the two potential barriers was suitable, and it provided a new way to enhance the spin injection efficiency from ferromagnet to semiconductor. Investigation shows that the high ferromagnet exchange energy is useful in enhancing SIN and TMR in the magnetic double tunnel junctions with asymmetric potential barrier, and can enhance SIE more than TMR. the increase of the ferromagnet exchange energy