Coupled Spin Ordering in the Ln2LiRuO6 Double Perovskites

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• 作者：Sophia J. Makowski ; Jennifer A. Rodgers ; Paul F. Henry ; J. Paul Attfield ; Jan-Willem G. Bos
• 刊名：Chemistry of Materials
• 出版年：2009
• 出版时间：January 27, 2009
• 年：2009
• 卷：21
• 期：2
• 页码：264-272
• 全文大小：497K
• 年卷期：v.21,no.2(January 27, 2009)
• ISSN：1520-5002

文摘

Synchrotron X-ray, neutron powder diffraction, and magnetic susceptibility measurements have been used to characterize the Ln₂LiRuO₆ (Ln = Pr, Nd, Sm, Eu, Gd, and Tb) double perovskites. All compositions have the monoclinic P2₁/n superstructure with a fully ordered arrangement of Li⁺ and Ru⁵⁺ cations. As the Ln-size decreases, the lattice volume decreases due to the increased tilting of the octahedra, but the Li−O and Ru−O distances remain constant. Antiferromagnetic transitions with Néel temperatures in the 20−35 K range were observed for all compositions, except for Gd₂LiRuO₆, which does not order down to 5 K. Nd₂LiRuO₆ shows a field-induced ferrimagnetic transition at 4 Tesla. The Ln = Pr, Nd, and Tb materials have type I magnetic structures with coupled spin ordering on the Ln and Ru sublattices. Critical fits reveal that the Ln³⁺ sublattice magnetization shows mean field behaviour (β ≈ 0.5), whereas the Ru⁵⁺ spin order is consistent with the three-dimensional Heisenberg model (β = 0.31−0.35).