Investigation of microstructure and magnetic properties of FePt films grown on different substrates

Different thickness (3, 5 and 10 nm) FePt films were fabricated on four typical single crystal substrates (MgO, KTaO3, SrTiO3 and LaAlO3), and the effects of lattice mismatch on the microstructure and magnetic properties of FePt films were systematically investigated. The XRD, SEM and TEM results showed that the different lattice mismatch between the substrates and FePt films resulted in the different crystallographic texture and microstructure of the FePt films. Under the tensile strain between the FePt and substrates (MgO, KTaO3, and SrTiO3), the FePt films preferred to form L10 FePt (001) texture. For the FePt films grown on the LaAlO3 substrate, FePt (110) orientations were preferred to be formed. Moreover, under the same FePt thickness, with the reduction in the lattice mismatch from MgO to KTO and STO (tensile stress), the morphologies of the FePt films changed from maze-like to continuous. For the FePt films grown on the LAO substrate (compressive stress), the FePt films maintained island growth mode.