Effect of substrate temperature on plasma-enhanced self-assembling formation of high-density FePt nanodots

Abstract

We formed FePt magnetic nanodots (NDs) by exposing an ultrathin bilayer metal stack on ∼3.0 nm SiO2/Si(100) substrates to a remote H2 plasma (H2-RP) and studied the effect of external heating during the exposure to H2-RP on the formation and magnetic properties of NDs. The ultrathin bilayer with a uniform surface coverage drastically changed to NDs with an areal density as high as ∼3.5 × 1011 cm−2 by exposing to H2-RP with external heating. We also found that NDs formed by the exposure to H2-RP at 400 °C exhibited a perpendicular anisotropy with a perpendicular coercivity of ∼1.5 kOe, reflecting the magneto-crystalline anisotropy of (001)-oriented L10 phase FePt.