JJAP Conference Proceedings

JJAP Conf. Proc. 2, 011305 (2014) doi:10.7567/JJAPCP.2.011305

Doppler-broadening of annihilation radiation spectroscopy under high magnetic field using a longitudinally spin-polarized slow positron beam

Masaki Maekawa, Hongjun Zhang, Hui Li, Yuki Fukaya, Atsuo Kawasuso

  1. Japan Atomic Energy Agency, Takasaki, Gunma 370-1292, Japan
  • Received June 11, 2014
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Abstract

A spin-polarized positron beam generated using a 22Na source, solid neon moderator and magnetic lens was developed. The beam diameter, beam flux and spin polarization were 0.5 mm, 1 × 105 e+ s−1 and 27%, respectively. An electromagnet system, which can generate ±1 T magnetic field, was also developed and equipped with the beam apparatus. Using this apparatus, Doppler broadening of annihilation radiation spectra under a high magnetic field were measured for bulk polycrystalline Fe, Co, and Ni samples and a thin film Co2MnSi sample. These spectra showed a clear asymmetry upon field reversal.

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