非化学量論組成FePt合金薄膜におけるL1_0規則相の低温合成と磁気特性

概要

論文の詳細を見る
L1_0 Ordered FePt alloy with large uniaxial magnetic anisotropy (K_u=7.0 × 10^7 erg/cc) has attracted much attention because of the thermal stability of magnetization in nanometer-scaled particles. Many studies have focused on the fabrication of L1_0 ordered FePt thin films. However, most of them have been limited to a narrow composition range, i.e., around the stoichiometric composition (Fe_<50>Pt_<50> in at.%) or Fe-rich compositions. In this work, we investigated the composition dependence of the chemical order S and uniaxial magnetic anisotropy K_u in Fe_xPt_<100-x> thin films sputterdeposited on MgO(001) substrate at reduced temperature. High S of 0.6±0.1 and large K_u of 1.8 × 10^7 erg/cc can be achieved in FePt(001) films even at 300℃ by choosing an off-stoichiometric composition for the Ptrich side (Fe_<38>Pt_<62>). Although the mechanism for promoting chemical order at reduced temperature is not clear at present, we may say that the strain from the underlayer plays a significant role in the formation of the L1_0 ordered structure.
社団法人日本磁気学会の論文
2004-04-01