Crystal structure and physical properties of ternary compounds RPt3B, R=La, Pr, Nd

The crystal structure of a new series of ternary rare-earth platinum borides RPt3B (R=La, Pr, Nd) has been studied by X-ray powder diffraction analyses from the 'as-cast' alloys. The tetragonal CePt3B structure type, space group P4mm (No. 99), has been confirmed for all compounds. Rietveld refinements for the two compounds, PrPt3B and NdPt3B, were performed. LaPt3B is a temperature-independent Pauli-type paramagnet from room temperature down to 4 K. PrPt3B orders antiferromagnetically at TN=15 K followed by a ferromagnetic spin flip at TC=5 K, whereas NdPt3B exhibits an antiferromagnetic spin alignment at a Neel temperature TN=7 K. The temperature dependence of the electrical resistivity, ρ(T), reflects the metallic character of these compounds. Furthermore the characteristic changes of slope of ρ(T) plots prove the magnetic transitions