Analytical Sciences

Abstract − Analytical Sciences, 24(1), 81 (2008).

Development of Spin-Polarized Ion Scattering Spectroscopy
Taku SUZUKI*,** and Yasushi YAMAUCHI*
*National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
**PRESTO, Japan Science and Technology Agency, 5-Sanbancho, Chiyoda, Tokyo 102-0075, Japan
Spin-polarized ion scattering spectroscopy using an electron-spin-polarized 4He+ ion beam was developed as a novel analytical method of the element selective spin state at outermost surfaces. Spin-polarized He+ ions were generated from the Penning ionization of metastable He 23S1 atoms (He*), which were spin-polarized by optical pumping (OP). The spin polarization of He* (PHe*) was observed to be the highest with an OP radiation density of about 0.05 W cm-2, and a further increase of the OP radiation density reduced PHe*. This decrease of PHe* is attributed to imperfect polarization of the OP radiation, hence optimization of the OP radiation density is essential to obtain He+ ions with high spin polarization. As a result of this optimization, we successfully observed the spin dependence of the scattered He+ ion yield on an Fe(100) surface exposed to an oxygen atmosphere.