Influence of Pt substitution on magnetic properties of multipolar ordering compounds Ce(Pd,Pt)3S4.

We have studied the magnetic properties of the multipolar ordering compounds Ce ( Pd 1 − x Pt x ) 3 S 4 with 0.00 ≤ x ≤ 0.53 by means of magnetic susceptibility and magnetization measurements. In CePd 3 S 4 , a simultaneous phase transition of the antiferro quadrupolar (AFQ) ordering and ferro magnetic (FM) ordering has been observed at 6.3 K. It has been suggested that the primary order parameter of CePd 3 S 4 is the quadrupole moments, and it has not been understood why the FM ordering occurs at very high temperature which is almost the same magnetic transition temperature of GdPd 3 S 4 . GdPd 3 S 4 shows an antiferromagnetic (AFM) transition at 5.8 K. With increasing Pt substitution in CePd 3 S 4 , the FM transition temperature T C ( x ) is rapidly suppressed to 2.4 K for x ≃ 0.3 and approaches asymptotically to 1.9 K ( x = 0.53 ) . The results of magnetization curve suggest that the ordered state below T C ( x ) remains FM and AFQ ordered state for the whole range of x . For x ≥ 0.29 , T C ( x ) reaches at around 2 K, a new AFM transition was observed at T N ( x ) ≃ 7 K . We determined the T − x phase diagram, and discuss the phase transitions at T C ( x ) and T N ( x ) . The results suggest the possibility of the presence of the correlation between the magnetic interaction and the quadrupole interaction, and the correlation is not understood based on the previous multipolar model. [ABSTRACT FROM AUTHOR]