New ternary Yb5Sb3-type R5PtX2 compounds (R = Y, Gd and Er; X = Sb and Bi) and their magnetic properties

Six novel Yb5Sb3-type compounds (space group Pnma) have been synthesized: Y5PtSb2, Gd5PtSb2, Er5PtSb2, Y5PtBi2, Gd5PtBi2 and Er5PtBi2. The Gd5PtSb2, Gd5PtBi2, Er5PtSb2 and Er5PtBi2 undergo a ferromagnetic-type ordering followed by lower-temperature field sensitive magnetic transitions.