Strontium Oxide Tunnel Barriers for High Quality Spin Transport and Large Spin Accumulation in Graphene.
Strontium Oxide Tunnel Barriers for High Quality Spin Transport and Large Spin Accumulation in Graphene.
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用于石墨烯中高质量自旋传输和大量自旋积累的氧化锶隧道势垒。
DOI：
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发表时间：
2017
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通讯作者：
Roland K. Kawakami
中科院分区：
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作者：
Simranjeet Singh;J. Katoch;T. Zhu;Ryan J. Wu;Adam S. Ahmed;W. Amamou;Dongying Wang;K. Mkhoyan;Roland K. Kawakami
铁磁体/石墨烯界面处的隧道势垒的质量通过规避阻抗失配问题、减少界面自旋相移机制以及减少回到铁磁体的自旋吸收，在石墨烯自旋阀中发挥着关键作用。因此，集成优异的隧道势垒以增强石墨烯中的自旋输运和自旋积累至关重要。在这里，我们在石墨烯上采用了一种新型隧道势垒氧化锶（SrO）来实现高质量的自旋输运，二氧化硅基底上的石墨烯的室温自旋弛豫时间超过一纳秒就证明了这一点。此外，通过分子束外延（MBE）生长的光滑且无针孔的SrO隧道势垒可以承受大的电荷注入电流密度，使我们能够在室温下实验性地实现石墨烯中的大自旋积累。这项工作使石墨烯走上了利用石墨烯中的自旋电流实现纳米磁体磁化的有效操纵的道路，用于逻辑和存储应用。
The quality of the tunnel barrier at the ferromagnet/graphene interface plays a pivotal role in graphene spin valves by circumventing the impedance mismatch problem, decreasing interfacial spin dephasing mechanisms and decreasing spin absorption back into the ferromagnet. It is thus crucial to integrate superior tunnel barriers to enhance spin transport and spin accumulation in graphene. Here, we employ a novel tunnel barrier, strontium oxide (SrO), onto graphene to realize high quality spin transport as evidenced by room-temperature spin relaxation times exceeding a nanosecond in graphene on silicon dioxide substrates. Furthermore, the smooth and pinhole-free SrO tunnel barrier grown by molecular beam epitaxy (MBE), which can withstand large charge injection current densities, allows us to experimentally realize large spin accumulation in graphene at room temperature. This work puts graphene on the path to achieve efficient manipulation of nanomagnet magnetization using spin currents in graphene for logic and memory applications.