High resolution magnetic force microscopy of patternedL10-FePt dot arrays by nanosphere lithography

Abstract

High resolution magnetic force microscopy (MFM) has been carried out onL10-FePt dot arrays patterned by plasma modified nanosphere lithography. An ex situ tipmagnetization reversal experiment is carried out to determine the magnetic domains andverify the imaging stability of MFM and the mutual perturbations between the magnetictip and the sample. We have identified that the critical size for the single domain region isabout 90 nm across. Comparison with MFM image simulation also suggests that themagnetizations of the triangular dots in both single and double domain states are parallelto one edge of the dots, indicating the large uniaxial magnetocrystalline anisotropy of theL10-FePt phase and the need for decreasing the magnetostatic energy.