Abstract The series of platinum-rich rare earth intermetallics RE 6 Pt 13 Zn 4 ( RE = Y, La-Nd, Sm, Gd-Ho) was synthesized by induction-melting of the elements in sealed niobium ampoules. X-ray powder data revealed isotypism with the sub-nitride Na 16 Ba 6 N according to Pt 12 Zn 4 RE 6 Pt with platinum-zinc ordering on the two crystallographically independent sodium sites. The structure of Ho 6 Pt 12.55(1) Zn 4.45 was refined from single crystal X-ray diffractometer data: Im3¯m , a = 941.36(2) pm, w R = 0.0312 for 172 F 2 values and 13 variables. Refinement of the occupancy parameters showed the formation of a small homogeneity range through Pt2/Zn mixing. The striking structural motif of the RE 6 Pt 13 Zn 4 series are Pt1 centered RE 6 octahedra in a bcc -type arrangement. These octahedra are surrounded by cages formed by the Pt2 and Zn atoms. Temperature dependent magnetic susceptibility measurements show stable trivalent rare earth ground states for all samples. Y 6 Pt 13 Zn 4 and La 6 Pt 13 Zn 4 show negative susceptibilities, i. e., the core diamagnetism overcompensates the Pauli contribution. Ferromagnetic ordering has been observed for RE = Ce ( T C = 4.1(1) K), Pr ( T C = 6.1(1) K), Nd ( T C = 3.5(4) K), Sm ( T C = 32.2(1) K), Gd ( T C = 22.9(1) K) and Dy ( T C = 5.7(1) K). Tb 6 Pt 13 Zn 4 is the only antiferromagnet ( T N = 8.7(1) K) and exhibits a metamagnetic transition at a critical field of 2.5(2) kOe. Ho 6 Pt 13 Zn 4 shows no magnetic ordering down to 2 K.
Baldauf et al. (Mon,) studied this question.