Study of the magnetic interactions in Ba2PrRu1−xCuxO6 using neutron powder diffraction

Abstract

High-resolution neutron powder diffraction has been used to determine the crystal and magnetic structures of Ba₂PrRuO₆ and Ba₂PrRu_0.90Cu_0.10O₆. Both materials are 2116 distorted double perovskites and the magnetic structure, which develops below ∼110 K, consists of two interpenetrating Type I antiferromagnetic sublattices of the Ru⁵⁺ and Pr³⁺ ions. When saturated, the moments are ∼1.9 μ_B for Ru⁵⁺ and ∼1.1 μ_B for Pr³⁺ in the c-direction, though copper doping introduces an extra ab-component of ∼0.65 μ_B. From the study of variable temperature neutron diffraction data the principal magnetic interactions in the materials have been determined. Although an overall antiferromagnetic structure is adopted, the Ru–O–Pr ferromagnetic interaction is a factor of ∼4 times stronger than the Ru–O–O–Ru antiferromagnetic interaction.