Structural and Magnetic Behavior of Cu/Ni Bilayer on Si(100) Surface

Cu/Ni thin films were deposited onto Si(100) substrate at room temperature by thermal evaporation of 99.99% pure Cu and Ni metals in high vacuum of 2.0 × 10^–5 mbar. The structural and magnetic properties were investigated using X-ray Diffractometer (XRD), Atomic Force Microscope (AFM), X-ray Photoelectron Spectroscopy (XPS) and Superconducting Quantum Interference device (SQUID) techniques. The XRD pattern of the Cu/Ni reveals the formation of bilayer on Si(100) substrate with average crystallite size is about 35 nm and well supported by AFM microstructure study. XPS studies indicate the presence of pure Cu on the surface after sputtering with argon ion beam. Some amount of Ni is observed at the interface which interacts with Cu. The peak of Cu 2p_3/2 occurs at 932.4 eV binding energy with a spin orbit separation of about 19.9 eV where as the Ni 2p_3/2 peak occurs at 853.0 eV with a spin orbit splitting of 17.5 eV. Cu/Ni bilayer exhibits weak ferromagnetism at room temperature due to interaction of Cu with Ni at the interface.