Bit patterned media based on block copolymer directed assembly with narrow magnetic switching field distribution

O Hellwig (1) , J.K. Bosworth (1) , E Dobisz (1) , D Kercher , Thomas Hauet (1) , G Zeltzer (1) , J. D. Risner-Jamtgaard (1) , D Yaney (1) , R Ruiz (1)

1 HGST San Jose Research Center

Electron-beam ͑E-beam͒ directed assembly, which combines the long-range phase and placement registration of e-beam lithography with the sharp dot size and spacing uniformity of block copolymer self assembly, is considered highly promising for fabricating templates that meet the tight magnetic specifications required for write synchronization in bit patterned media magnetic recording systems. In our study, we show that this approach also yields a narrower magnetic switching field distribution ͑SFD͒ than e-beam patterning or block copolymer self-assembly alone. We demonstrate that the pattern uniformity, i.e., island diameter and placement distributions are also important for achieving tight magnetic SFDs. Bit patterned media ͑BPM͒ magnetic recording systems at densities in excess of 1 Tb/ in 2 require an extremely tight lithographic bit placement accuracy and a narrow size distribution of less than 5% in order to achieve good write synchronization between the recording head and the patterned media. 1 Nanoimprint technology with master molds fabricated via e-beam directed assembly of block copolymer films is considered a very promising cost-effective approach for creating highly uniform magnetic dot patterns over large areas. 2,3 In addition to the tight lithographic specifications for BPM, a narrow switching field distribution ͑SFD͒ of the magnetic dots is critical to ensure exact bit addressability without overwriting adjacent bits.

Mots clés: magnetic recording; bit pattern media; nanomagnetism; switching field distribution; nanopatterning

Domaines: Science des matériaux [cond-mat.mtrl-sci]

O Hellwig, J.K. Bosworth, E Dobisz, D Kercher, Thomas Hauet, et al.. Bit patterned media based on block copolymer directed assembly with narrow magnetic switching field distribution. Applied Physics Letters, 2010, ⟨10.1063/1.3293301⟩. ⟨hal-01345344⟩