Europhys. Lett., 56 (5) , pp. 722-728 (2001)
Electronic-structure modifications induced by surface segregation in thin filmsC. N. Borca1, B. Xu1, T. Komesu1, H.-K. Jeong1, M. T. Liu1, S.-H. Liou1, S. Stadler2, Y. Idzerda2 and P. A. Dowben1
1 Department of Physics and Astronomy and the Center for Material Research and Analysis, Behlen Laboratory, University of Nebraska Lincoln, NE 68588-0111, USA
2 Material Physics Branch, Naval Research Laboratory - Washington DC 20375, USA
(Received 11 July 2001; accepted in final form 20 September 2001)
Using spin-polarized inverse photoemission and X-ray absorption spectroscopy techniques, we show that the electronic structure of thin films depends on the composition at the surface. With a gentle annealing procedure, the surface provides a maximum of 80% spin asymmetry at 0.5 above the Fermi level in spite of extensive segregation. A heavily annealed (restructured) surface exhibits a reduced surface "ordering" temperature of 240 (compared to the approximately 335 bulk value) as well as a reduced spin asymmetry value of 40% at 0.5 above Fermi energy.
73.20.-r - Electron states at surfaces and interfaces.
68.35.Fx - Diffusion; interface formation.
75.25.+z - Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source X-ray scattering, etc.).
© EDP Sciences 2001