Ferromagnetism in Pr-rich binary Pr7Ru3 intermetallic compound

We present the synthesis and experimental characterization of the binary intermetallic compound Pr7Ru3. The polycrystalline sample was prepared by arc melting pure Pr and Ru, followed by homogenization at 500 °C and 600 °C for 48 and 89 h, respectively. Powder x-ray diffraction confirms that Pr7Ru3 crystallizes in an orthorhombic crystal structure (Pnma, space group no. 62) with the lattice parameters: a = 7.3606(7) Å, b = 23.120(1) Å and c = 6.5959(5) Å. Magnetization, resistivity, and heat capacity measurements reveal a ferromagnetic transition in Pr7Ru3 with the Curie temperature TC ∼ 24.5 K. The bulk transition is confirmed by a large λ-shape anomaly observed in the specific heat measurement. The magnetic susceptibility above the transition obeys the modified Curie-Weiss law with a positive Curie-Weiss temperature ϴCW = 30(1) K and an effective magnetic moment of 3.39(1) μB/Pr. Resistivity data for Pr7Ru3 reveals metallic-like behavior with a clear anomaly at the transition temperature which is smeared by an applied magnetic field. We also synthesized high-quality nonmagnetic analog La7Ru3 for which superconducting transition is observed with Tc = 1.95 K, in agreement with the literature. •Pr7Ru3 is a new (soft) ferromagnetic intermetallic compound with the Curie temperature 24.5 K.•Above TC the χ(T) data follows a Curie-Weiss law, with the fitting parameters ϴCW = 31(3) K and μeff = 3.32(1) μB/Pr.•Heat capacity measurements confirm a bulk transition and suggest a non-Kramers magnetic doublet as a ground state of Pr7Ru3.