High Field Mossbauer Investigations of the Magnetic Phase Transition in Sc sub 0.25 Ti sub 0.75 Fe sub 2 at 4.2K

Mossbauer measurements in applied fields up to 13.5 T on Sc sub 0.25 Ti sub 0.75 Fe sub 2 are reported. The hysteretic behaviour observed in the field dependence of the bulk magnetization is also visible in the Mossbauer spectra, but hysteresis in the hyperfine fields is only found for Fe on 6h sites. In low external fields, the hyperfine fields on these sites form a cone (opening angle approx 140 deg ) with the resulting field parallel to those of 2a sites. At high fields, the cone angle drops to zero and all hyperfine fields are antiparallel to the applied field. The field induced phase transition can be described as a transition from canted ferromagnetism to ferromagnetism of the Fe atoms occupying the 6h positions. Graphs. 12 ref.--AA