Microstructure and Magnetic Properties of In-Situ Deposited $L1_{0}$ FePt Films on MgO(200) Films of Varying Thicknesses

Abstract

The FePt(30 nm)/MgO bilayer films with various MgO(200) underlayer thicknesses of 0 to 30 nm are in-situ deposited on Si substrates. A weak (111) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> peak as well as strong (001) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> and (002) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> peaks are observed in XRD pattern of single-layered FePt film with no MgO underlayer. When a 5 nm thick MgO film is introduced under the FePt film, the (111) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> peak almost disappears and both the (001) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> and (002) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> peaks are enhanced greatly. This indicates that the perpendicular magnetic anisotropy of FePt film can be improved by introduction of a thinner MgO underlayer. However, a weak (111) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FePt</sub> peak appears again as the MgO underlayer is increased to 10 nm, revealing that the perpendicular magnetic anisotropy of FePt film will be deteriorated by introducing a thicker MgO underlayer.