SGER: New Magnetic Tunnel Junctions Using Semiconductor Sandwich Layers with Controllable Band Gaps

D.C.Jiles和j.e.s nider超越100 gb /in2的数据存储密度需要材料的革命。磁隧道结提供了一种可能的解决方案，并有望成为未来磁盘驱动器读磁头的重要组成部分，这是每年500亿美元硬盘驱动器行业的一部分。去年宣布的隧道交汇处的R/R为30%。然而，目前的隧道结存在严重的问题，它们完全基于氧化铝阻挡层。这些层的厚度现在降到了0.7纳米，但隧道结的电阻对于预期的应用来说仍然太高。从本质上讲，氧化铝隧道结已经达到了其最终性能极限，并且由于高电阻，氧化铝隧道结是否能够用于读磁头和MRAM是一个问题。因此，基于替代势垒层的新型隧道结材料是时候提出了。Fert等人最近对替代绝缘体材料的研究表明，势垒层对磁性层中的自旋极化有很强的影响。Freitas等人研究了在氧化铝中添加氮的影响，当成分从Al2O3变为AlN时，氮改变了势垒高度，导致隧道磁电阻从22%增加到25%。然而，这些都没有解决设备整体电阻的核心问题。在我们提出的SGER中，我们打算进行彻底的改变，用其他半导体完全取代氧化铝。当然，这是一个高风险的尝试，但如果项目成功，将为磁性数据存储行业带来巨大的好处，这是一个值得探索的研究。

D.C.Jiles and J.E.SnyderProgress beyond data storage densities of 100 Gbits/in2 requires a revolution in materials. Magnetic tunnel junctions provide a possible solution and are expected to form an essential component of future magnetic disk drive read heads, part of the $50 billion/year hard disk drive industry. Tunnel junctions with a R/R of 30% have been announced in the last year. However there are serious problems with the current generation of tunnel junctions, which are based exclusively on an alumina barrier layer. These layers are now down to 0.7 nm in thickness and still the resistances of the tunnel junctions are too high for the intended applications. Essentially the alumina tunnel junction has reached its ultimate performance limits and there is a concern if alumina tunnel junctions will ever be able to be used in read heads and MRAM because of the high resistance. Therefore it is time for new tunnel junction materials to be brought forward based on alternative barrier layers. Recently studies of alternative insulator materials by Fert et. al. showed that the barrier layer strongly affects the spin polarization in the magnetic layers. Freitas et al. have studied the effect of nitrogen additions to the alumina which changed the barrier height and resulted in an increase in tunnel magnetoresistance from 22% to 25% as the composition changed from Al2O3 to AlN. However none of this has addressed the central problem of the overall resistance of the devices. In our proposed SGER we intend to make the radical change of completely replacing the alumina with other semiconductors. Of course this is a high risk endeavor, but the enormous benefits to the magnetic data storage industry that will accrue if the project is success make this a worthwhile exploratory investigation.