Interfacial mixing of ultrathin Cr films grown on an Fe whisker

1/2-ML Cr films grown on an Fe whisker have been studied using angle-resolved Auger electron forward scattering as a function of the substrate temperature at which the Cr was deposited. The angular scans of the peak-to-peak Cr Auger intensity show pronounced peaks due to forward scattering, which indicate significant intermixing of Cr atoms into the second layer for films grown at 100, 180, and 246 degrees C, and into the third layer for the film grown at 296 degrees C. Calculations based on a single-scattering theory show that half of the Cr deposited at 296 degrees C is below the surface. Since previous studies of exchange coupling through Cr films used samples grown at this elevated temperature, the alloying may be related to the earlier finding that the exchange coupling through Cr(001) is much weaker than, and of opposite phase to, that predicted by first-principles calculations.