Interdiffusion Phenomena and Magnetic Properties of Deposited Co/Cu/Co Trilayers on Silicon Wafers

In this study, the surface morphologies of multilayers were observed by scanning electron microscope and atomic force microscope, the microstructure evolution of annealed Co/Cu/Co trilayers deposited on silicon wafers was investigated by means of Auger electron spectroscope and X-ray diffraction. Changes in the magnetic properties of annealed Co/Cu/Co trilayers were studied by vibrating sample magnetometer. The results clearly showed coherent epitaxial growth in the as-deposited Co/Cu/Co trilayers, while the coherent epitaxial structure was damaged after annealing at 200 °C. We found that the Co/Cu/Co trilayers revealed stable layer stacking up to 400 °C, and then the Cu displayed obvious tendency to diffuse toward the Co layer at 500 °C employed by AES concentration depth profile method. Owing to the interdiffusion of Cu and Co annealed at 500 °C, the interfacial structure changed to form an intermixing layer with the lamellar structure losing. With increasing annealing temperature, saturation magnetization decreased and coercivity of trilayers increased. Overall, these findings suggest that interdiffusion in Co/Cu/Co trilayers is one of the important factors which caused deterioration of the magnetic properties.