Spin valve effect of NiFe/graphene/NiFe junctions  

作　　者：Muhammad Zahir Iqbal Muhammad Waqas Iqbal Jae Hong Lee Yong Seung Kim Seung-Hyun Chun Jonghwa Eom 

机构地区：[1]Department of Physics and Graphene Research Institute, Sejong University, Seou1143-747, Korea

出　　处：《Nano Research》2013年第5期373-379,380,共8页纳米研究（英文版）

摘　　要：When spins are injected through graphene layers from a transition metal ferromagnet, high spin polarization can be achieved. When detected by another ferromagnet, the spin-polarized current makes high- and low-resistance states in a ferromagnet/graphene/ferromagnet junction. Here, we report manifest spin valve effects from room temperature to 10 K in junctions comprising NiFe electrodes and an interlayer made of double-layer or single-layer graphene grown by chemical vapor deposition. We have found that the spin valve effect is stronger with double-layer graphene than with single-layer graphene. The ratio of relative magnetoresistance increases from 0.09% at room temperature to 0.14% at 10 K for single-layer graphene and from 0.27% at room temperature to 0.48% at 10 K for double-layer graphene. The spin valve effect is perceived to retain the spin-polarized transport in the vertical direction and the hysteretic nature of magnetoresistance provides the basic functionality of a memory device. We have also found that the junction resistance decreases monotonically as temperature is lowered and the current-voltage characteristics show linear behaviour. These results revealed that a graphene interlayer works not as a tunnel barrier but rather as a conducting thin film between two NiFe electrodes.当旋转从一种转变金属铁磁物质通过 graphene 层被注射时，高旋转极化能被完成。当由另一种铁磁物质检测了时，极化纺纱的电流在一个 ferromagnet/graphene/ferromagnet 连接造成高抵抗、低抵抗的状态。这里，我们在包括用化学蒸汽免职种的双层或单个层的 graphene 做的 NiFe 电极和夹层的连接向 10 K 从房间温度汇报明白旋转阀门效果。我们发现了旋转阀门效果比与单个层的 graphene 与双层 graphene 是更强壮的。在在在在为双层 graphene 的 10 K 的到 0.48% 的房间温度的为单个层的 graphene 并且从 0.27% 的 10 K 的到 0.14% 的房间温度的从 0.09% 的相对磁致电阻增加的比率。旋转阀门效果被察觉在垂直方向保留极化纺纱的运输，磁致电阻的 hysteretic 性质提供一台记忆设备的基本功能。当温度被降低，我们也发现了连接电阻 monotonically 减少并且当前电压的特征表演线性行为。这些结果表明 graphene 夹层不作为一个隧道障碍，但是相当作为进行工作在二个 NiFe 电极之间的薄电影。

关 键 词：GRAPHENE spin valve magnetic junction MAGNETORESISTANCE SPINTRONICS 

分 类 号：TN6[电子电信—电路与系统] O413[理学—理论物理]