Morphology induced magnetoresistance enhancement of tunneling junctions with the Heusler electrode Co2Cr0.6Fe0.4Al
Morphology induced magnetoresistance enhancement of tunneling junctions with the Heusler electrode Co2Cr0.6Fe0.4Al
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DOI：
10.1063/1.3114425
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发表时间：
2009-04-06
影响因子：
4
通讯作者：
Jourdan, Martin
中科院分区：
文献类型：
--
作者：
Herbort, Christian;Jorge, Elena Arbelo;Jourdan, Martin
当半金属铁磁体用于具有多晶AlOx势垒的磁性隧道结时，预计会有很大的磁电阻。我们用原位隧道显微镜证明了Co2Cr0.6Fe0.4Al Heusler薄膜原子光滑的形貌是如何导致Al层在氧化后形成隧道势垒的不利的润湿性能的。在Co2Cr0.6Fe0.4Al/Al界面处插入一层非常薄(2.5A)的镁层，极大地改变了Al的生长模式。结果表明，隧道磁阻(TMR)明显增强[Co2Cr0.6Fe0.4Al/AlOx/Co70Fe30结：TMR(4K)=101%]。相应的Julliere自旋极化达到67%，比以前报道的该化合物的值要大。
A large magnetoresistance is expected when half-metallic ferromagnets are used in magnetic tunneling junctions with polycrystalline AlOx barrier. We demonstrate by in situ tunneling microscopy how the atomically smooth morphology of Co2Cr0.6Fe0.4Al Heusler thin films results in unfavorable wetting properties of the Al layer, which forms the tunneling barrier after oxidation. The insertion of a very thin (2.5 A) Mg layer at the Co2Cr0.6Fe0.4Al/Al interface changes the growth mode of the Al drastically. As a result the tunneling magnetoresistance (TMR) is clearly enhanced [Co2Cr0.6Fe0.4Al/AlOx/Co70Fe30 junction: TMR(4 K)=101%]. The corresponding Julliere spin polarization amounts to 67%, larger than previously reported values for this compound.