Element selective magnetism in Ho0.5Nd0.5Fe3(BO3)4 single crystal probed with hard X-ray magnetic circular dichroism

Abstract We present a study of a Ho 0.5 Nd 0.5 Fe 3 ( BO 3 ) 4 single crystal aiming at understanding the roles of each magnetic sublattices in magnetic transitions at low temperatures. The crystal structure is determined to have the R 32 symmetry in whole studied temperature range but the crystal appears to be racemic. Element selective magnetic properties studied with X-ray magnetic circular dichroism at the L 2 , 3 -edges of Ho and Nd, and at the Fe K -edge at T  = 3 K under magnetic fields of ±17 T are compared with the results of macroscopic magnetization measurements in pure and substituted crystals. All three magnetic sublattices are shown to be strongly coupled and to undergo a spin-reorientation transition when magnetic field is applied along the trigonal c -axis. On the contrary, when magnetic field is applied in the ab -plane only the holmium atoms exhibit a sizeable magnetization jump. This result allows us to conclude that the spin-flop transitions observed in macroscopic magnetization curves and associated anomalies of electric polarization are due to the Ho 3+ magnetic moment reorientation.