Interface morphology of a Cr(001)/Fe(001) superlattice determined by scanning tunneling microscopy and x-ray diffraction: A comparison
Schmidt, CM × Burgler, DE Schaller, DM Meisinger, F Guntherodt, HJ Temst, Kristiaan #
Amer inst physics
Journal of Applied Physics vol:89 issue:1 pages:181-187
A Cr(001)/Fe(001) superlattice with ten bilayers grown by molecular beam epitaxy on a Ag(001) substrate is studied by in situ scanning tunneling microscopy (STM) and ex situ x-ray diffraction (XRD). Layer-resolved roughness parameters determined from STM images taken in various stages of the superlattice fabrication are compared with average values reported in the literature or obtained from the fits of our XRD data. Good agreement is found for the rms roughnesses describing vertical roughness and for the lateral correlation lengths characterizing correlated as well as uncorrelated interface roughness if peculiarities of STM and XRD are taken into account. We discuss in detail (i) the possible differences between the STM topography of a free surface and the morphology of a subsequently formed interface, (ii) contributions due to chemical intermixing at the interfaces, (iii) the comparison of XRD parameters averaged over all interfaces versus layer-resolved STM parameters, and (iv) the question of the coherent field of view for the determination of rms values. (C) 2001 American Institute of Physics.