Fabrication and characterization of CoPt nanodot arrays by nanoimprint lithography and electrodeposition
CoPt nanodot arrays of 50nm in diameter and 100nm pitch were fabricated by nanoimprint lithography and electrodeposition process. A polymer mold used was replicated from a Si master mold with nanopatterns which were fabricated by EBL and ICP-RIE, where hydrophobic surface of these was achieved by FOTS coating. UV-NIL was successfully performed under pressures of 5MPa for 5min with an UV exposure time of 30s, where the substrate was Ru (30nm)/NiFe (10nm)/Ta (5nm)/Si (100). The size of patterns was measured at 53nm in diameter, 25nm in height, 100nm in pitch. Finally, CoPt nanodot arrays were galvanostatically electrodeposited and characterized. The size and the composition of these arrays were measured to be 50nm in diameter and 100nm in pitch and Co-23.6 at.% Pt, respectively. According to MFM analysis, these arrays for the remnant states represent a single domain structure of perpendicular direction with a magnetic field, where a field of 15kOe was applied perpendicular to the sample plane. These results show that for the CoPt dot arrays of 50nm diameter perpendicular magnetic signal can be recorded and switched.
nanoimprint lithography nanopatterning cobalt platinum alloy perpendicular magnetic recording