Magnetic properties of Ba2Y1-xCuxTaO6-δ solid solutions.

• Polycrystalline specimens of Ba 2 Y 1- x Cu x TaO 6-δ were synthesized by the solid-state reaction route. • The magnetic properties of the Ba 2 Y 1- x Cu x TaO 6-δ solid solutions were investigated and reported for the first time. • The Cu for Y substitution induces paramagnetism and the onset of antiferromagnetic correlations. We carried out a study of the structural and magnetic properties of Ba 2 Y 1- x Cu x TaO 6- δ (0.0 ≤ x ≤ 0.5) compounds. The cubic rock-salt double perovskite structure of Ba 2 YTaO 6 is retained upon the partial substitution of Cu for Y up to x = 0.50 and the lattice parameter a drops at the rate of da/dx ≈ −0.17 ± 0.01 Å/%Cu. While the effective moment μ eff and the Curie-Weiss temperature θ CW are nearly negligible in Ba 2 YTaO 6 , the partial substitution of Cu for Y results shows an increase in μ eff at the rate of ≈ 1.9 ± 0.2 µ B /%Cu, consistently with the paramagnetic behavior expected for Cu2+, and a decrease in θ CW at the rate of −16 ± 2 K/%Cu. The drive of θ CW towards more negative values is suggestive of the onset of antiferromagnetic correlations. [ABSTRACT FROM AUTHOR]