MOSSBAUER STUDY OF FIELD-DRIVEN SPIN REORIENTATIONS IN YBFEO3 AT 4.2-K

Fe-57 Mossbauer absorption spectra have been recorded at 4.2 K for various single-crystal samples of the rare-earth orthoferrite YbFeO3 in applied magnetic fields up to 10 T. A field applied along the easy antiferromagnetic (c) axis induced, as expected, the Fe spins to 'flop' to being perpendicular to the field. Fields applied along the a and b crystal axes induced reorientations of the spins respectively towards and around the applied-field direction, the spins rotating towards the a axis in both cases. An explanation of these unusual reorientations is offered in terms of Fe-Yb spin decoupling.