Quantitative structural determination using spin-polarized low-energy electron diffraction rotation curves: W(110)

Spin-polarized low-energy electron diffraction (LEED) rotation curves measu red with 30 to 80 eV electrons scattered from a W(110) surface have been an alysed with calculations using a relativistic multiple scattering theory, w here quantitative reliability factors (R-factors) have been used to find th e best fit between theory and experiment. The Zanazzi-Jona ii-factor was us ed for intensity data, and the mean-squared deviation between theory and ex periment was used for the spin-polarization data. The variance of the ii-fa ctors for rotation curves has been derived, and varies as E-1/4 (where E is the scattering energy). This was used to estimate parameter uncertainties. The surface layer relaxation of W(110) was found to be -2.2+/-1.0% of the bulk layer spacing, in agreement with recent current-voltage LEED studies. These results illustrate that quantitative structural studies using low sca ttering energies may be performed with spin-polarized LEED rotation curves. This technique should be well suited to studies of magnetic ultrathin film s, where magnetic-exchange scattering becomes more predominant at low scatt ering energies. (C) 2000 Elsevier Science B.V. All rights reserved.