Multi-heterostructured spin-valve junction of vertical FLG/MoSe2/FLG
Muhammad Farooq Khan,
Shania Rehman,
Malik Abdul Rehman,
Rizwan Ur Rehman Sagar,
Deok-kee Kim,
H. M. Waseem Khalil,
Pragati A. Shinde,
Najam ul Hassan,
Pradeep Raj Sharma,
Jonghwa Eom,
Seong Chan Jun
Affiliations
Muhammad Farooq Khan
Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, South Korea
Shania Rehman
Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, South Korea
Malik Abdul Rehman
Department of Nanotechnology and Advanced Material Engineering and Graphene Research Institute, Sejong University, Seoul 05006, South Korea
Rizwan Ur Rehman Sagar
School of Materials Science and Engineering, Jiangxi University of Science and Technology, Jiangxi 341000, People’s Republic of China
Deok-kee Kim
Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, South Korea
H. M. Waseem Khalil
Department of Electrical Engineering, College of Engineering and Technology, University of Sargodha, Sargodha, Pakistan
Pragati A. Shinde
School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea
Najam ul Hassan
University of Central Punjab, Sargodha, Pakistan
Pradeep Raj Sharma
Department of Physics and Astronomy and Graphene Research Institute-Texas Photonics Center International Research Center (GRI–TPC IRC), Sejong University, Seoul 05006, South Korea
Jonghwa Eom
Department of Physics and Astronomy and Graphene Research Institute-Texas Photonics Center International Research Center (GRI–TPC IRC), Sejong University, Seoul 05006, South Korea
Seong Chan Jun
School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea
Two-dimensional (2D) layered materials and their heterostructures have opened a new avenue for next-generation spintronic applications, benefited by their unique electronic properties and high crystallinity with an atomically flat surface. Here, we report magnetoresistance of vertical magnetic spin-valve devices with multi-layer (ML) MoSe2 and its heterostructures with few-layer graphene (FLG). We employed a micro-fabrication procedure to form ultraclean ferromagnetic–non-magnetic–ferromagnetic interfaces to elucidate the intrinsic spin-transferring mechanism through both an individual material and combinations of 2D layered materials. However, it is revealed that the polarity of tunneling magnetoresistance (TMR) is independent of non-magnetic spacers whether the spin valve is composed of a single material or a hybrid structure, but it strongly depends on the interfaces between ferromagnetics (FMs) and 2D materials. We observed positive spin polarizations in ML-MoSe2 and FLG/ML-MoSe2/FLG tunnel junctions, whereas spin-valve devices comprised of FLG/ML-MoSe2 showed a reversed spin polarization and demonstrated a negative TMR. Importantly, in Co/FLG/ML-MoSe2/FLG/NiFe devices, the polarization of spin carriers in the FM/FLG interface remained conserved during tunneling through MoSe2 flakes in spin-transferring events, which is understandable by Julliere’s model. In addition, large TMR values are investigated at low temperatures, whereas at high temperatures, the TMR ratios are deteriorated. Furthermore, the large values of driving ac-current also quenched the amplitude of TMR signals. Therefore, our observations suggest that the microscopic spin-transferring mechanism between ferromagnetic metals and 2D materials played a momentous role in spin-transferring phenomena in vertical magnetic spin-valve junctions.
