Electronic-structure modifications induced by surface segregation in $\chem{La_{0.65}Pb_{0.35}MnO_{3}}$ thin films

C. N. Borca; B. Xu; T. Komesu; H.-K. Jeong; M. T. Liu; S.-H. Liou; S. Stadler; Y. Idzerda; P. A. Dowben

doi:doi:10.1209/epl/i2001-00580-y

DOI: 10.1209/epl/i2001-00580-y

Europhys. Lett., 56 (5) , pp. 722-728 (2001)

Electronic-structure modifications induced by surface segregation in $\chem{La_{0.65}Pb_{0.35}MnO_{3}}$ thin films

C. 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

pdowben@unl.edu

(Received 11 July 2001; accepted in final form 20 September 2001)

Abstract
Using spin-polarized inverse photoemission and X-ray absorption spectroscopy techniques, we show that the electronic structure of $\chem{La_{0.65}Pb_{0.35}MnO_{3}}$ 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 $\un{eV}$ above the Fermi level in spite of extensive $\chem{Pb}$ segregation. A heavily annealed (restructured) surface exhibits a reduced surface "ordering" temperature of 240 $\un{K}$ (compared to the approximately 335 $\un{K}$ bulk value) as well as a reduced spin asymmetry value of 40% at 0.5 $\un{eV}$ above Fermi energy.

PACS
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

Electronic-structure modifications induced by surface segregation in thin films

Electronic-structure modifications induced by surface segregation in $\chem{La_{0.65}Pb_{0.35}MnO_{3}}$ thin films