Preparation and characterisation of epitaxial Pt/Cu/FeMn/Co thin films on (100)‐oriented MgO single crystals

Abstract

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.FeMn/Co thin-films, a purely metallic exchange-bias system, were prepared on (100)-oriented MgO single crystals. The layers were grown by molecular beam epitaxy (MBE). The crystalline and magnetic properties could be tuned by using sputtered Pt buffer layers deposited at variable temperatures. A transition of the crystalline orientation from (111)-terminated layers at lower deposition temperatures to (100)-terminated layers at temperatures higher than 950 K was established and the impact on the magnetic sample properties was investigated. Here, the detailed sample preparation process is shown together with low energy electron diffraction (LEED), medium energy electron diffraction (MEED), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements revealing the samples structure and composition. The crystalline orientation of Pt was imprinted to the magnetic layer stack and clearly influenced the exchangebias (EB) and coercive field (H C ) as shown by superconducting quantum interference device (SQUID) and magneto-optical Kerr effect (MOKE) measurements. Furthermore, a correlation between the crystallite size and the temperature dependent magnetic properties could be identified.

Ab Initio Guided Low Temperature Synthesis Strategy for Smooth Face–Centred Cubic FeMn Thin Films

“…The multi-layered FeMn based thin film model systems as well as magnetic devices require sharp interfaces for a meaningful determination and understanding of interface dominated properties like coherency effects [14] or EB [15]. The sputter deposition of FeMn based model systems on rigid oxide substrates requires relatively high deposition temperatures of up to 450 • C for the fcc phase formation, which is reported to be accompanied by high thin film roughness of up to 170 nm for film thicknesses in the order of 2 µm [16][17][18][19].…”

“…Schmidt et al used MgO (a MgO = 4.210 Å [28]) substrates for the molecular beam epitaxy (MBE) synthesis of the EB FeMn/Co. thin-films due to its cubic structure and lattice mismatch of about 16% for cube-on-cube orientation on FeMn [15]. Sapphire (α-Al…”