Spin-polarized low energy electron diffraction studies of Cu¿Au(001)
Lind, David Melvin
Walters, G. King
Master of Arts
Combined measurements in low-energy electron diffraction of both intensity and diffracted electron spin-polarization are obtained for Cu,Au(1). Here the use of polarized LEED represents a refinement over standard LEED techniques because additional and complementary data is obtained. In addition, the recent implementation of a spin-modulated polarized electron source allows the rapid and simultaneous acquisition of PLEED I-V and P-V spectra. The order-disorder transition at the Cu,Au(1) surface, near the bulk transition temperature (at Tc=391°C), seems only slightly to affect PLEED profiles. The polarization of the (1) beam has been studied as a function of temperature between room temperature and 44°C. Although significant polarizations were noted, no dramatic transition-dependent polarization changes were found. Temperature dependent changes in the profiles are noted, and may be attributed to standard thermal scattering according to the Debye-Waller factor. In addition, angular studies of the specular diffraction were obtained, and may be used to characterize the ordered state at room temperature.