Patterning micro- and nano-structured FePt by direct imprint lithography

The merits of high thermal stability and active chemical catalysis make FePt a suitable material for various purposes such as recording media and catalysts for growing carbon nanotubes. Comparing to other micro and nano patterning techniques such as electron beam lithography and X-ray lithography, imprint patterning is of low cost and high throughput, making it the most promising method for mass manufacturing at micro and nano scales. Direct imprint lithography using functional materials as resist avoids the etching process which introduces defects and errors. Here we use direct imprint to pattern the FePt-containing polymer in order to acquire different micro- and nano-structured FePt on silicon wafers. Regularly- arranged hole and line arrays with periodicity down to 400 nm were acquired on the PDMS stamps. Using direct imprint lithography, the negative copies of the PDMS stamps were successfully transferred to silicon substrates as characterized by scanning electron microscopy (SEM). The magnetic force microscopy (MFM) images showed that the ferromagnetic properties of the patterns were all well preserved after annealing, indicating this direct imprint patterning method can effectively pattern FePt on silicon substrates at both micro- and nano-scales with the magnetic properties retained.