L10-FePt(001) single-crystal films were grown epitaxially on SrTiO3(001), MgAl2O4(001), and MgO(001) substrates. Their uniaxial magnetic anisotropy Ku and the order structure were examined for the film thickness t range of 2-14nm. All series of films show large Ku of 4×107erg/cm3 in the thickness range higher than 10nm, with order parameter S of 0.8 and saturation magnetization Ms of 1120emu/cm3. Ku decreased gradually as t decreased. The Ku reduction was considerable when t decreased from 4nm to 2nm. No marked difference in the thickness dependence of Ku was found in any series of films, although the lattice mismatch between FePt and the substrates was markedly different. K u reduction showed good agreement with the reduction of S for the films on MgAl2O4 and MgO. The Ku ∼S 2 plot showed an almost linear relation, which is in good agreement with theoretical predictions. Transmission electron microscopy images for a FePt film on MgO substrate revealed that the lattice mismatch between FePt(001) and MgO(001) was relaxed in the initial 1 or 2 layers of FePt(001) lattices, which is likely to be true also for two other series of films.
ASJC Scopus subject areas
- Physics and Astronomy(all)