Open AccessMagnetoresistance effect in a vertical spin valve fabricated with a dry-transferred CVD graphene and a resist-free process
Author(s) -
Pradeep Raj Sharma,
Praveen Gautam,
Jungtae Nam,
Keun Soo Kim,
Hwayong Noh
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/abad03
Subject(s) - magnetoresistance , graphene , materials science , spin valve , resist , chemical vapor deposition , ferromagnetism , spintronics , electron beam lithography , condensed matter physics , fabrication , magnetic anisotropy , magnetic field , spin polarization , optoelectronics , layer (electronics) , nanotechnology , electron , magnetization , physics , medicine , alternative medicine , pathology , quantum mechanics
One of the most prominent and effective applications of graphene in the field of spintronics is its use as a spacer layer between ferromagnetic metals in vertical spin valve devices, which are widely used as magnetic sensors. The magnetoresistance in such devices can be enhanced by a selection of suitable spacer materials and proper fabrication procedures. Here, we report the use of dry-transferred single- and double-layer graphene, grown by chemical vapor deposition (CVD), as the spacer layer and the fabrication procedure in which no photo-resist or electron-beam resists is used. The measured maximum magnetoresistance of NiFe/CVD-Graphene/Co junction is 0.9% for the single- and 1.2% for the double-layer graphene at 30 K. The spin polarization efficiency of the ferromagnetic electrodes is about 6.7% and 8% for the single- and the double-layer graphene, respectively, at the same temperature. The bias-independent magnetoresistance rules out any contamination and oxidation of the interfaces between the ferromagnet and the graphene. The magnetoresistance measured as a function of tilted magnetic field at different angles showed no changes in the maximum value, which implies that the magnetoresistance signal is absent from anisotropic effects.