Study of half-metals using spin-polarized positron annihilation

Kawasuso, Atsuo; Maekawa, Masaki; Fukaya, Yuki   ; Mochizuki, Izumi

Heusler alloys are anticipated as promissing spin-injection electrode materials. In its evaluation, half-metallicity and spin-polarization are important factors. In our previous studies, spin-polarized positron annihilation spectroscopy (SP-PAS) is found to be useful for studying electronic state of ferromagnet. In this study, we performed SP-PAS measurements for a few Heusler alloys (CoMnAl, CoMnSi, NiMnSb). Consequently, we found that the majority spin band of CoMnAl has a d-like character, while those of CoMnSi and NiMnSb have sp-like characters. These findings are consistent with what expected from a band calculation.