New ternary aluminides Ce0.67Pd2Al5, Ce1.33Pd3Al8, and Ce1.74Pd5.29Al11.71

Polycrystalline samples of novel compounds Ce0.67Pd2Al5, Ce1.33Pd3Al8, and Ce1.74Pd5.29Al11.71 were prepared by arc-melting. The crystal structure of the latter compound was determined from the single-crystal X-ray diffraction data to be a disordered variant of the hexagonal Th2Ni17 type [P6(3)/mmc, a = 9.1961(5) angstrom, c = 8.8861(5) angstrom]. The crystal structures of the other aluminides were examined by powder X-ray diffraction and found to be isotypic with Sc0.67Fe2Si5 [P63/mmc, a = 4.3385(5) angstrom, c = 16.5255(15) angstrom] and Gd1.33Pt3Al8 [R (3) over barm, a = 4.37960(10) angstrom, c = 39.1683(9) angstrom], respectively. Based on the thermodynamic and electrical resistivity data measured down to 0.4 K in external magnetic fields up to 9 T, the new materials were characterized as metallic Curie-Weiss paramagnets due to fairly stable trivalent Ce ions. In Ce1.33Pd3Al8, an antiferromagnetic ordering was established below T-N = 2.3 K, while no long-range magnetic order was found in the other compounds. All three phases exhibit electrical conductivity that is governed by the interplay of Kondo and crystalline electric field interactions, and significantly affected by structural disorder inherent to their crystal lattices. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Polycrystalline samples of novel compounds Ce0.67Pd2Al5, Ce1.33Pd3Al8, and Ce1.74Pd5.29Al11.71 were prepared and their properties were characterized. The crystal structure of Ce1.74Pd5.29Al11.71 was determined to be a disordered variant of the hexagonal Th2Ni17 type, while the crystal structures of the other compounds were isotypic with known compounds. The materials exhibited metallic magnetism and electrical conductivity, influenced by the structural disorder of their crystal lattices.