@misc{oai:repo.qst.go.jp:00081022,
 author = {Maekawa, Masaki and Miyashita, Atsumi and Kawasuso, Atsuo and Maekawa, Masaki and Miyashita, Atsumi and Kawasuso, Atsuo},
 month = {Nov},
 note = {Positronium (Ps) is a quasi-stable bound system consisting of an electron and a positron. From the annihilation ratio of Ps decay, the spin polarization of electrons containing in Ps can be determined. Since Ps is formed only at a topmost surface region with a low-electron density, the spin polarization obtained by this method is not affected by the bulk condition. If the energy-resolved and spin-polarized Ps annihilation spectroscopy is available, one can obtain the spin-polarized electron density-of-states (DOS) associated with only the top-surface layer of materials. We have been developing SP-PsTOF apparatus for the energy-resolved and spin-polarized Ps annihilation spectroscopy.  From the SP-PsTOF spectrum obtained for a Ni film, the negative polarization near the Fermi level was obtained. This result is reproduced by a theoretical calculation. The SP-PsTOF method is expected to be most powerful tool for the study of materials for spintronics application., 4th QST International Symposium -Innovation from Quantum Materials Science-},
 title = {Development of spin-polarized positronium time-of-flight spectroscopy},
 year = {2020}
}