Nanopatterned L10-FePt nanoparticles from single-source metallopolymer precursors for potential application in ferromagnetic bit-patterned media magnetic recording

Bit-patterned media (BPM) with a precise stoichiometry ratio of Fe and Pt atoms are promising for future high areal density magnetic recording. Here, we report a new FePt-containing metallopolymer P as the single-source precursor for the synthesis of magnetic metal alloy nanoparticles. This polymer was synthesized from a random copolymer poly(styrene-4-ethynylstyrene) PES-PS and the bimetallic precursor TPy-FePt ([Pt(4′-ferrocenyl-(N^N^N))Cl]Cl) by the CuI-catalyzed dehydrohalogenation. After pyrolysis of P, the stoichiometry of Fe and Pt atoms in the synthesized nanoparticles is nearly close to 1 : 1, which is more precise than that by using TPy-FePt as the precursor. Also, polymer P is more suitable for patterning by high-throughput nanoimprint lithography (NIL) compared to TPy-FePt. Ferromagnetic nanolines, potentially useful for fabricating bit-patterned magnetic recording media, were successfully obtained from P and fully characterized.