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 

作者机构：Department of Physics and Graphene Research Institute Sejong University Seou1143-747 Korea 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2013年第6卷第5期

页      面：373-379,380页

核心收录：

学科分类：080903[工学-微电子学与固体电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 08[工学] 070201[理学-理论物理] 0702[理学-物理学] 

基　　金：supported by Nano-Material Technology Development Program Priority Research Centers Program Mid-career Researcher Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology supported by Converging Research Center Program through the Ministry of Education, Science and Technology 

主　　题：graphene spin valve magnetic junction magnetoresistance spintronics 

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.