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Non-destructive patterning of 10nm magnetic island array by phase transformation with low-energy proton irradiation

2017-10-09
Dutta, Tanmay
PATHAK, Sachin
ASBAHİ, Mohamed
Celik, Kubra
Lee, Jong Min
Yang, Ping
Saifullah, M. S. M.
Oral, Ahmet
Bhatia, C. S.
CHA, Jongin
HONG, Jongill
Yang, Hyunsoo
Nano-patterning on the order of sub-10 nm is integral to achieve high-density nano-scale devices for various data storage and data processing applications. However, the additional requirement of planarization and unwanted side-effects of physical or chemical etching have so far limited the patterning of sub-10nm devices. In this work, we have demonstrated the creation of an array of similar to 10nm ferromagnetic islands through selective phase transformation of paramagnetic multilayers by low-energy proton irradiation. Paramagnetic Co3O4/Pd multilayers masked with patterned PMMA (polymethyl methacrylate) were reduced to ferromagnetic Co/Pd by proton irradiation. A clear contrast of the nano-islands was observed using magnetic force microscopy, establishing the formation of ferromagnetic nano-islands with perpendicular magnetic anisotropy. This process provides a way to circumvent the side-effects associated with both conventional nano-scale pattering and high-energy ion irradiation. Therefore, phase transformation by low energy proton irradiation can be used for patterning sub-10nm nano-islands, not only for magnetic data storage but also for patterning various opto-electronic and spintronic devices. Published by AIP Publishing.