Magnetic Patterning through Graphene Protection against Oxidation and Interlayer Diffusion
Chak Ming Liu1*, Wei-Hsiang Wang1, Pei-Hsun Jiang1, Wen-Chin Lin1
1department of physic, National Taiwan Normal University, Taipei, Taiwan
* Presenter:Chak Ming Liu,
Graphene (Gr) has been demonstrated to protect metallic thin films against oxidation. Based on this idea, we propose a new method to fabricate micro-structured magnetic domains using patterned single-layer Gr. In the first experiment, single-layer Gr was transferred onto a CoPd alloy film pre-grown on a SiO2/Si(001) substrate. Subsequently, the single-layer Gr was patterned through electron beam lithography followed by oxygen plasma etching to expose selective micron-sized areas of CoPd. The exposed areas of CoPd were more easily oxidized compared to the areas protected by Gr, which is found to result in significant magnetic contrast between the protected and surface-oxidized areas of CoPd. In the second experiment, a lithographically-patterned Gr layer was placed between the Fe and CoPd films to block interlayer diffusion area- selectively during sample annealing, and magnetic contrast was observed to be established between the Pd/Fe/Gr/CoPd and Pd/Fe/CoPd areas, leading to a magnetic structure that matched the Gr patterning. These observations demonstrate that Gr patterning is a simple and powerful method of fabricating spintronic devices.

Keywords: Graphene, oxidation, interlayer diffusion, magnetic structure