Structural properties of ultrathin bcc Co (001) layers

摘要

Ultrathin layers (2-6 atomic monolayers) of the body-centered cubic (bcc) Co phase have been investigated by X-ray diffraction. Single-crystalline MgO (00 1) substrates and thin layers of Fe have been used to stabilize a (00 1) oriented single-crystalline bcc Co structure. The Co-on-Fe (Co deposited on Fe) interfaces in the Fe/Co superlattices are found to be abrupt up to a substrate temperature of about 500℃ whereas the Fe-on-Co (Fe deposited on Co) interfaces become more diffuse at 350℃ due to interdiffusion of Fe into the Co layers. The structural quality of the Fe/Co superlattices exhibits a strong temperature dependence. A marked decrease of the linewidth of the Fe/Co (002) Bragg peak with increased growth temperature is found for superlattices with high Co content. The decrease is attributed to the interdiffusion of Fe into the bcc Co layers.