Browsing by Author "Waters, Kelley Lyle"
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Item Spin-polarized electron emission spectroscopy (SPEES): A new and novel technique in surface science and ferromagnetism(1989) Waters, Kelley Lyle; Rau, CarlA new technique, Spin-Polarized Electron Emission Spectroscopy (SPEES), capable of investigating surface magnetism, has been successfully developed. SPEES allows us to energy- and spin-analyze electrons emitted during the interaction of a grazing-incidence ion beam with a solid surface. The energy and spin information obtained from the emitted electrons helps us to unravel the processes involved in ion-surface interactions at grazing angles. SPEES data obtained at Ni(110) picture-frame single crystals exhibit new characteristic features in the electron energy distribution that are strikingly different from that of electron-induced spectra. For the first time, two electron capture measurements, which are sensitive to "local" magnetic order existing on an atomic scale, have been performed at low energies (15-30 keV) at surfaces of the amorphous ferromagnet Fe$\sb{80}$B$\sb{20}$; the non-zero electron spin polarization amounts to 55%. These two new techniques open the way to study surface electronic and magnetic properties with unprecedented sensitivity.Item Surface magnetism study of nickel(110) and platinum-manganese-antimony using spin polarized electron emission spectroscopy (SPEES)(1991) Waters, Kelley Lyle; Rau, CarlA spin polarized electron emission spectroscopy (SPEES) study of several ferromagnetic samples has been performed. SPEES studies involve the energy- and spin-analysis of electrons emitted normal to the surface of a sample during grazing angle ion-surface reflection. The information obtained from the emitted electrons allows us to characterize the surface electronic, magnetic, and chemical structure, as well as processes occurring during ion-surface interactions. Studies were made on Ni(110) surfaces bombarded with H$\sp+$ and He$\sp+$ ions at an energy of 25 keV. Electron intensity distributions exhibit distinct features that are strikingly different from large-angle ion- and electron-induced electron emission spectra. Polarization data obtained allow us to unravel various physical processes occurring at the surface. Studies made on PtMnSb samples again show distinct and pronounced peaks and features which are more apparent in SPEES spectra than in any other spectroscopy. The studies made on these samples, using SPEES, show the power of this new spectroscopy to characterize and understand particle-surface interaction processes previously not well understood.