One-dimensional tellurium chains: Crystal structure and thermodynamic properties of PrCuxTe2 (x ~ 0.45)

Highlights: • Single crystals of PrCu_0.45Te₂ were grown in KI flux. • PrCu_0.45Te₂ is composed of edge and corner-sharing CuTe₄ tetrahedra and Pr-centered polyhedra. • The Cu site is partially occupied and exhibits signatures of local disorder. • Low-temperature heat capacity measurements of PrCu_0.45Te₂ reveal possible spin frustration behavior. -- Abstract: X-ray diffraction, crystal structure, magnetization, and heat capacity results are presented for the rare earth – chalcogenide ternary system PrCu_0.45Te₂ and its non-4f analogue LaCu_0.40Te₂. The crystal structure of PrCu_0.45Te₂ is characterized by chains of edge and corner-sharing CuTe₄ tetrahedra and Pr centered in polyhedra comprised of Cu and Te. The Cu site is partially occupied and exhibits signatures of local disorder. Magnetic susceptibility measurements show a Curie-Weiss temperature dependence consistent with a Pr³⁺ state. No magnetic ordering is observed down to 1.8 K, but the negative Curie-Weiss temperature suggests an antiferromagnetic exchange interaction. Importantly, the low temperature heat capacity of PrCu_0.45Te₂ is strongly enhanced by comparison to LaCu_0.40Te₂, suggesting that there is a build-up of entropy that is associated with the 4f-electrons from the Pr³⁺ ions. These features reveal possible spin frustration behavior and introduce this family of materials as a template for studying new phenomenon.