HGST reports (13 June 2016) using template-assisted epitaxial growth to create 1 Tdot / in2 bit-patterned media including servo patterning. The template is established by nano-imprinting on a carefully chosen materials stack such that subsequent processing induces oxide growth between platinum pillars, enhancing magnetic separation of the islands (bits) and ensuring single domains within each one. The pattern growth process takes advantage of both chemical and topological contrast.
Embedded servo patterning permits the final media to be manufactured without a separate servo writing step. The growth process results in topography favorable to flying head aerodynamics, while maintaining adequate magnetic contrast in the servo regions.
Reference: Yang et al., “Template-Assisted Direct Growth of 1 Td/in2 Bit Patterned Media”, Nano Lett. (2016), DOI: 10.1021/acs.nanolett.6b02345. [Also, arXiv:1606.05370.]