Particulate FePt/Ag(C) films with strong perpendicular anisotropy

Textured FePt∕Ag and FePt∕C multilayers have been fabricated by dc magnetron sputtering onto single crystal MgO (100) substrates at elevated temperatures from 280to400°C using FePt, Ag, and C targets. Our studies showed that isolated and ordered L10 FePt nanoparticles with perpendicular magnetic anisotropy can be formed in these multilayers. The (FePt∕Ag) multilayers showed a lower transformation temperature from the disordered fcc to the ordered L10 phase than the FePt∕C multilayers. The lowest temperature to form the L10 phase is found to be 280°C in FePt∕Ag multilayers. The c-axis texture can be improved by increasing the thickness of Ag layers. As the deposition temperature is increased, the degree of atomic ordering approaches that of the fully ordered phase. The magnetic and structural properties are consistent with the microstructure studies observed with high-resolution transmission electron microscopy.