High-field magnetization study of single-crystal

Abstract
We report measurements of the c-axis magnetization of single crystals, both unannealed and annealed, in fields up to 20 T. From our results, we conclude that the kink-type anomaly in the magnetization has a different high-field dependence from the dipole moment as seen in neutron diffraction experiments. Within the experimental error, we are unable to observe the effects of heat treatment on the field dependence. We discuss these new findings together with recent high-field results of resistivity and neutron diffraction experiments.