Background
The interest in ultra-thin magnetic films has been steadily increasing since they are the building blocks of spintronic applications such as data storage devices and magnetic random access memory. However, structural characterization of the interfaces of ultrathin films with possible chemical reactions and formation of new crystalline phases has always been a challenge in materials research.
Investigation
The SmartLab multi-purpose diffraction system configured with a state of the art independent in-plane scanning arm is best suited for the study of ultra-thin films. The example shown here is a 2 nm elemental Fe film deposited on top of 10 nm of CuO on silicon. The sample was annealed in vacuum at 300°C for 30 minutes. The measurement was performed with a 2.2 kW Cu sealed-tube X-ray source.
Figure 1 shows the measured in-plane XRD profile and the identified phases. Clearly, the 2 nm elemental iron has been oxidized to Fe₃O₄ while the CuO has been reduced to elemental copper due to the chemical reactions at the interfaces.
Figure 2 shows the X-ray reflectivity (XRR) profile of the same sample along with a simulation of the calculated layer structure. The XRR analysis confirms the in-plane XRD results and provides additional information about the Fe3O4; and copper layer thicknesses.
