Investigation of magnetic substances by means of polarized positron annihilation spectroscopy

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

We are investigating magnetic substances by means of polarized positron annihilation spectroscopy with Ge-Ga source. We so far found that the Doppler broadening of annihilation radiation (DBAR) spectra of Fe, Co, Ni and Gd exhibit so-called field-reversal asymmetry. In this study, we investigated detailed field dependences of the field-reversal asymmetry. For Fe and Co, we found that the field-reversal asymmetry of the DBAR spectra show hysteresis like the magnetization curve. For Ni and Gd, we found somewhat different features from those of Fe and Co. These differences are explained considering the band structure and its field splitting.