Crystal structure and physical properties of new ternary RPt2B compounds, R=La, Pr, Nd

A new series of ternary rare-earth platinum borides RPt2B (R=La, Pr, Nd) has been synthesized by arc melting and structurally characterized using X-ray powder diffraction method. Compounds were found to crystallize with the CePt2B structure type, space group P6222 (No. 180), Z=3. LaPt2B is a temperature independent Pauli-type paramagnet from room temperature down to 4 K. PrPt2B orders antiferromagnetically at a Néel temperature TN=4.6 K, whereas NdPt2B exhibits an antiferromagnetic spin alignment at TN=18 K followed by a ‘ferromagnetic’ spin flip at TC=10 K. The temperature dependence of the electrical resistivity, ρ(T), reflects the metallic character of these compounds. Furthermore the charactristic changes of slope of ρ(T) plots confirm the magnetic transitions.