Electric-field-induced extremely large change in resistance in graphene ferromagnets
Electric-field-induced extremely large change in resistance in graphene ferromagnets
复制标题
电场引起石墨烯铁磁体电阻发生极大变化
DOI：
10.1088/1361-6463/aa9b5e
复制
发表时间：
2018-01-17
影响因子：
3.4
通讯作者：
Song, Yu
中科院分区：
文献类型：
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作者：
Song, Yu
巨磁阻（类似于100 × 10（3）%）和极大的磁阻（类似于1 × 10（6）%）之前已分别在锰氧化物钙钛矿和狄拉克材料中进行了探索。然而，极强磁场（和极低温度）的要求使其不适用于现实设备。在这项工作中，我们提出了一种可以在零磁场和高温下产生更大电阻变化的器件。该器件由两条钇铁石榴石（YIG）下的石墨烯组成，其中施加两个栅极电压以抵消YIG诱导的半金属铁磁体中的重电荷掺杂。通过Landauer-Buttiker公式的计算，我们证明了在液氦（氮）温度和零磁场条件下，当在自由铁磁体上施加适当的栅压时，可以实现高达305 × 10（6）%（16 × 10（3）%）的电阻变化。我们将这种显著的效应归因于自由铁磁体中的栅极诱导全极化反转，这导致器件中的金属态到绝缘体态的转变。我们还发现，所提出的效果可以实现在使用其他磁性绝缘体，如EuO和EuS的设备。我们的工作应该有助于开发一个现实的开关设备，是节能和CMOS技术兼容。
A colossal magnetoresistance (similar to 100 x 10(3)%) and an extremely large magnetoresistance (similar to 1 x 10(6)%) have been previously explored in manganite perovskites and Dirac materials, respectively. However, the requirement of an extremely strong magnetic field (and an extremely low temperature) makes them not applicable for realistic devices. In this work, we propose a device that can generate even larger changes in resistance in a zero-magnetic field and at a high temperature. The device is composed of graphene under two strips of yttrium iron garnet (YIG), where two gate voltages are applied to cancel the heavy charge doping in the YIG-induced half-metallic ferromagnets. By calculations using the Landauer-Buttiker formalism, we demonstrate that, when a proper gate voltage is applied on the free ferromagnet, changes in resistance up to 305 x 10(6)% (16 x 10(3)%) can be achieved at the liquid helium (nitrogen) temperature and in a zero magnetic field. We attribute such a remarkable effect to a gate-induced full-polarization reversal in the free ferromagnet, which results in a metal-state to insulator-state transition in the device. We also find that the proposed effect can be realized in devices using other magnetic insulators, such as EuO and EuS. Our work should be helpful for developing a realistic switching device that is energy saving and CMOS-technology compatible.