Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK.
J Phys Condens Matter. 2013 Dec 11;25(49):496008. doi: 10.1088/0953-8984/25/49/496008. Epub 2013 Nov 6.
Non-conservation of magnetic neutron scattering from the six-layer hexagonal perovskite Ba3CaRu2O9 on cooling reveals that (Ru(5+))2 dimers form nonmagnetic spin-singlet ground states. This is in contrast to Ba3BRu2O9 (B=Co or Ni) analogues which display long range spin ordered ground states containing antiferromagnetic (Ru(5+))2 dimers (Lightfoot and Battle 1990 J. Solid State Chem. 89 174). Dimer formation is weakly coupled to the lattice, resulting in an excess [101] microstrain broadening of diffraction peaks at low temperatures. Non-conservation of magnetic neutron scattering is also observed around the charge ordering transition in Ba3NaRu2O9 showing that the ground state structure is coupled to spin-singlet formation in charge ordered Ru2O9 dimers.
冷却过程中，来自六层六方钙钛矿 Ba3CaRu2O9 的非保守磁中子散射表明（Ru(5+))2 二聚体形成非磁性单自旋基态。这与 Ba3BRu2O9（B=Co 或 Ni）类似物形成对比，后者显示出具有反铁磁（Ru(5+))2 二聚体的长程自旋有序基态（Lightfoot 和 Battle 1990 J. Solid State Chem. 89 174）。二聚体的形成与晶格弱耦合，导致低温下衍射峰的[101]微应变展宽增加。在 Ba3NaRu2O9 的电荷有序转变周围也观察到非保守磁中子散射，表明基态结构与电荷有序 Ru2O9 二聚体中单自旋形成耦合。
