Resonant magnetic x-ray diffraction study on the successive metamagnetic transitions of TbB4 up to 30 T

Abstract

We report the results of resonant magnetic x-ray diffraction experiments in pulsed high magnetic fields on TbB4, which exhibits successive metamagnetic transitions between 16 and 28 T. The observed field, polarization, and scattering angle dependence of the diffracted intensity indicates that magnetic moments perpendicular to the magnetic field exist in the high-field plateau phases. This result is clearly inconsistent with normal fractional magnetization plateau phases that have magnetic moments only parallel or antiparallel to the field. In order to resolve this discrepancy, we propose magnetic structures consisting of Ising spins and XY spins. A possible mechanism that produces these novel magnetic structures is also discussed.