3D atom probe investigation of (Fe/Dy) magnetic multilayers

(Fe 3nm/Dy 2nm) 30 multilayers were deposited at 300 and 600 K by thermal evaporation under ultrahigh vacuum on (111) oriented Si substrates and investigated by SQUID magnetometry. Their hysteresis loops show that the magnetic properties strongly depend on the deposition temperature, since the perpendicular magnetic anisotropy (PMA) is much higher for the sample deposited at 600 K. To understand this phenomenon, a careful investigation of the structure and chemistry of the multilayers was carried out using a 3D atom probe. Some (Fe/Dy) multilayers were deposited on W tips at room temperature and analysed by tomographic atom probe. A 3D reconstruction and a composition profile were obtained, which made it possible to observe the structure and composition of the multilayer at the atomic scale.