New ternary intermetallics RE5Ru3Al2 (RE = La, Ce, Pr): Synthesis, crystal structures, magnetic and electric properties

作者：Murashova E V^*; Tursina A I; Bukhanko N G; Nesterenko S N; Kurenbaeva Zh M; Seropegin Y D; Noel H; Potel M; Roisnel T; Kaczorowski D

来源：Materials Research Bulletin, 2010, 45(8): 993-999.

DOI：10.1016/j.materresbull.2010.04.006

• Intermetallic compounds
• X-ray diffraction
• Crystal structure
• Magnetic properties
• Electrical properties

Intermetallics RE5Ru3Al2 (RE = La, Ce, Pr) were prepared by arc melting of the elemental components with subsequent annealing at 820 K. The crystal structures were determined from single-crystal (Ce5Ru3Al2, Pr5Ru3Al2) and powder (La5Ru3Al2) X-ray diffraction at room temperature. The compounds belong to new structural types: space group R3, Z = 6, a = 13.9270(3) angstrom, c = 8.3260(2) angstrom for Ce5Ru3Al2 and space group I2(1)3, Z = 4, a = 9.95419(6) angstrom and 9.8084(3) angstrom for La5Ru3Al2 and Pr5Ru3Al2, respectively. The trigonal structure of Ce5Ru3Al2 is a distorted variant of the cubic La5Ru3Al2 and Pr5Ru3Al2 structures. An interesting feature of the Ce5Ru3Al2 are the short (2.5299(16) angstrom and 2.5969(15) angstrom) Ce-Ru distances. Magnetic measurements revealed the Pauli paramagnetic behavior in La5Ru3Al2 and the Curie-Weiss paramagnetism in Pr5Ru3Al2. The latter compound likely exhibits a kind of magnetically ordered state below 24 K. In turn, Ce5Ru3Al2 remains paramagnetic down to 4.2 K and shows signs of mixed valence states of Ce ions. Electrical resistivity measurements indicated simple metallic conductivity in La5Ru3Al2 and Pr5Ru3Al2, and a more complex metallic behavior in Ce5Ru3Al2.

• 出版日期2010-8