We investigated the structural and magneto-transport properties of Fe/SrO/MgO/Fe magnetic tunnel junctions (MTJs), in which SrO has a large lattice mismatch (Δ a / a ∼ 21%) with Fe. Despite such a large Δ a / a , structural analyses revealed that a fully epitaxial Fe(001)/SrO(001)/MgO(001)/Fe(001) structure was successfully formed. We observed high magnetoresistance (MR) ratios up to 98% at 20 K (65% at room temperature), suggesting that coherent spin-polarized tunneling occurs through the SrO(001) tunnel barrier. We also demonstrated that the resistance-area product and bias-voltage ( V half ), at which the MR ratio reaches half of the zero-bias value, were comparable to the values reported in epitaxial Fe/MgO/Fe MTJs. Since SrO has a smaller Δ a / a with Si (∼5%) than that between MgO and Si (∼23%), the results offer that this material is a promising candidate as a high-quality tunnel barrier for Si-based spin transport devices.<...

中文翻译：

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晶格不匹配的外延Fe / SrO / MgO / Fe磁性隧道结的结构和磁输运性质

我们研究了Fe / SrO / MgO / Fe磁性隧道结（MTJs）的结构和磁传输性质，其中SrO与Fe的晶格失配较大（Δa / a〜21％）。尽管有这么大的Δa / a，但结构分析表明成功形成了完全外延的Fe（001）/ SrO（001）/ MgO（001）/ Fe（001）结构。我们观察到在20 K（室温下为65％）时高达98％的高磁阻（MR）比，这表明相干自旋极化隧穿通过SrO（001）隧道势垒发生。我们还证明，MR比达到零偏压值的一半时的电阻面积积和偏置电压（V half）与外延Fe / MgO / Fe MTJs中报道的值相当。由于SrO在Si中的Δa / a（〜5％）比在MgO和Si之间的Δa / a（〜23％）小，