Peculiar magnetic phase diagrams of GdPd2Si2 single crystal

Abstract

High field magnetization measurement were performed up to 45 T using a long pulse magnet on a GdPd2Si2 single crystal compound having the tetragonal ThCr2Si2-type crystal structure and an antiferromagnetic ordering of TN=16.7 K. The magnetization processes are almost typical antiferromagnetic ones with a weak magnetic anisotropy though small anomalies exist in the processes. The magnetization saturates 7 μB/f.u. above Bs=32 T. The B001-T and B100-T magnetic phase diagrams were constructed. There are three phases, the phase I, II and III, under non-magnetic field in the ordered state for both diagrams. The field-induced phase, phase IV, appears below the paramagnetic phase by the [100] magnetic field, B100, which is accompany with a re-entrant behaviour. The B100 makes the phase II be stable and the phase I and III be instable. These strange behaviours indicate the direction of the magnetic moment changes in each phase.