Studies of the Gd Overlayer on Cr by Synchrotron Radiation Photoemission

The formation of Gd/Cr interface, the growth mechanism and electronic structure of Gd overlayers were investigated by synchrotron radiation photoemission. It is shown that Gd adatoms interact with the Cr substrate weakly. A lower deposition rate of the Gd overlayer (1.0 A/min) favors the smooth growth of Gd/Cr interface. However, higher deposition rate (6.0 A/min) leads to the cluster growth of the Gd overlayer and the presence of a "two-peak" feature of Gd 4f emission. We correlate this feature with the different coordination number of surface atoms derived from cluster- induced surface roughness.