Formation of lanthanide-platinum alloys by reaction of platinum with lanthanide iodides Part II. Structural and magnetochemical investigations into the systems with Ln ≜ Nd, Gd, Tb, Dy, Tm2

Abstract The synthesis of Ln-Pt alloys (Ln ≜ Nd, Gd, Tb, Dy, Tm) at 800°C in the presence of iodine is described. In the case of Nd and Gd the phases LnPt 5 , LnPt 3 and LnPt 2 are produced depending on the residual ratio n 1 / n Ln (Ln amount less the alloying proportion). Using the same conditions for the systems with Tb, Dy, and Tm, only LnPt 5 and LnPt 3 are obtained. The single-phase and two-phase intermetallic reaction products with Ln ≜ Nd, Gd, and Tb are magnetochemically analysed on the basis of the Curie-Weiss law (Gd, Tb) and the crystal field/molecular field model (Nd). The thermodynamic interpretation of the reactions shows that besides the heats of formation of the lanthanide diiodides, further factors have to be considered.