Extreme doping sensitivity of the ordering direction in GdCo12-xFexB6
Résumé
Gd-155 Mossbauer spectroscopy has been used to investigate the magnetic ordering direction of GdCo12-xFexB6 (0 <= x <= 3) at 5K. The moment orientation was found to be extremely sensitive to doping with as little as similar to 4% Fe doping (0.5 Fe/f.u.) causing the moment orientation to change from the c-axis to the basal plane. Including results from earlier Fe-57-doping work suggests that the axial-basal boundary may lie below 0.5% Fe doping (similar to 0.06 Fe/f.u.). As the ordering directions for the other R Co12B6 compounds have all been derived from Fe-57-doped samples, a re-evaluation of these compounds may be necessary.