Fabrication of ultrafine L1₀-FePt-based magnetic patterns enabled by single-step nanoimprint-assisted block copolymer self-assembly

Abstract

The bit islands in magnetic patterns play a crucial role in advancing magnetic recording density, but the trade-off issues between miniaturization and scalable production are still challenging. Here we present a two-in-one technique of nanoimprint lithography (NIL)-assisted self-assembly using a specially engineered FePt-containing block copolymer (BCP), offering a simple one-step fabrication for L10-FePt bit-patterned media with high throughput. This method combines top-down NIL with bottom-up self-assembly to precisely control the ultrafine magnetic bits in the nanoscale patterns. The FePt-derived BCPs, designed with an equal atomic ratio of Fe and Pt, ensure the preparation of homogeneously dispersed L10-FePt nanoparticles (NPs). Subsequent BCP pyrolysis results in NPs with enhanced magnetic properties, significantly advancing high-density data storage devices. This strategy offers a novel approach to drive the innovative creation of ordered magnetic metal alloy NPs arrays for practical applications.