Nano- and micro-patterning biotemplated magnetic CoPt arrays.

Patterned thin-films of magnetic nanoparticles (MNPs) can be used to make high‑density data storage devices. High coercivity MNPs (e.g. L10 CoPt) are nano-patterned to create this bit-patterned media (BPM). This increases storage capacity by reducing bit size, which is highly desirable in developing smaller recording media for consumer devices . Conventional manufacture of BPM is not environmentally friendly as it uses high temperatures (500˚C) and high vacuum, which requires specialised equipment. To tackle these issues, we have taken inspiration from nature to create patterns of CoPt using a biotemplating peptide under mild conditions. Nano-patterning via interference lithography (IL) and micro-patterning using micro-contact printing (μCP) were used to create a peptide resistant mask onto a gold surface under ambient conditions. We redesigned a biotemplating peptide to self-assemble onto gold surfaces (cgsgktheihspllhk), and mineralised the patterns at 18˚C in water. Ferromagnetic CoPt is biotemplated by the immobilised peptides, and the patterned MNPs maintain stable magnetic domains. This bioinspired study offers an ecological route towards developing biotemplated.