Fabrication of FePt type exchange coupled composite bit patterned media by block copolymer lithography

Hao Wang, M. Tofizur Rahman, Haibao Zhao, Yosuke Isowaki, Yoshiyuki Kamata, Akira Kikitsu, Jian Ping Wang

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29 Scopus citations

Abstract

We fabricated exchange coupled composite (ECC) L10 ordered, (001) oriented FePt (5nm)/Fe (5 nm) bit patterned media over a large area by diblock copolymer lithography. We formed the dot arrays of the copolymer directly on the magnetic film and used them as the etching mask. The average size of the ECC FePt/Fe pillars was about 32 nm, with a center to center distance of about 35 nm and a size distribution of about 8. The perpendicular coercivity (Hc) of the ECC FePt/Fe patterned structures was about 4.3 kOe. Both the coercivity and the saturation field of the ECC FePt/Fe patterned structure were reduced by about 50 due to the exchange coupling between FePt and Fe in the FePt/Fe patterned structure compared to the FePt patterned structure with similar dot size and distribution. The thermal stability and gain factor of the FePt/Fe ECC structure were about 260 kBT and 1.35, respectively.

Original languageEnglish (US)
Article number07B754
JournalJournal of Applied Physics
Volume109
Issue number7
DOIs
StatePublished - Apr 1 2011

Bibliographical note

Funding Information:
This work is partially supported by the INSIC extremely high areal density recording (EHDR) program, Western Digital, the NSF MRSEC program under Award Number DMR-0819885, and the NSF Nano Fabrication Center (NFC) at the University of Minnesota. Parts of this work were carried out in the University of Minnesota I.T. Characterization Facility, which receives partial support from the NSF through the NNIN program.

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